Hello! In case you didn’t know, our latest Core Expansion, By God Alone, launches on 30 September, which is tomorrow. Aside from trying to explain why September doesn’t have a 31st, we’ll walk you through several topics we normally cover right before release: Art, Music, Modding, and Achievements - all in one Diary!
We also have some new faces to introduce: a dedicated UGC Experience (UGCx) team has been working hard to improve moddability, and in recent months they've added many features modders have been requesting for years. We'll hear from them later in this Diary.
Let's dive in.
Hello! Anton Holmqvist here, Art Lead on By God Alone, which takes a deep dive into the Catholic church. The Christian Church has a deep well of references to take inspiration from so I’m here to show you what the team came up with!
Key Art
We first did the key art in-house for Khans of the Steppe which turned out amazing. So for By God Alone we got to do it again! This was one of the first art works we started working on for this DLC. This was also due to it being marketing material which needs to be done earlier than a loading screen for example. But it began as an idea from our Game Director, who kinda saw this vision of a puppet theater in some way with clerical puppets being controlled by secular rulers somehow. So we started exploring this idea to come up with something that both pushes the art envelope of what marketing art can be, but also takes into account the marketing of the expansion and what it communicates.
[Composition sketches and color sketch in the center of the design we decided to go with]
[Finished key art for By God Alone, showing secular rulers puppeteering the people around the church to bend it in their favor]
Loading Screen
Loading screens are the introduction to our DLCs and the biggest task our illustrators have. This is so we can ensure you have something that is filled with story and details that will reveal something new every time you look at it. But before you see the finished artwork, we always start with sketches exploring different compositions and themes.
[Composition sketches]
We decided on going forward with the illustration taking inspiration from Thomas Becket, the archbishop of Canterbury, who was assassinated by four knights inside the Canterbury Cathedral loyal to King Henry II. The sketch highlighted that the church wasn't just a place for worship, but also a place of conflict and intrigue. Once we’ve agreed on a sketch we usually do some color variations where we can explore the mood further, flesh out the composition or look for a palette which we haven't really used before.
[Color sketches once we decided on which sketch to progress with]
[Finished loading screen and what you will see when playing By God Alone for the first time!]
Story Event Illustrations
To show the chapters of the Christian Church we decided to make story event illustrations categories which could include two of the phases. These could then be cropped to fit the theme of the specific phase when shown in “The Christian Church” interface but displayed in its full glory when triggered as a regular story event. We did end up making a unique illustration for the “Crusade” phase since we didn’t feel any of the first batch of illustrations fit the theme well enough.
[Sketches for the different phases of the Christian Church]
Below you can see all the finished illustrations in this order: Zeal, Concord, Crisis, Crusade and Instability.
[The finished illustrations, each fitting two phases of the Christian Church. Except “Zeal” which we later in production split, making “Crusade” into its own illustration that fit the theme better.]
Legacy Track
With the legacy track we want to bring in a lot of different themes. In this illustration you can see many different parts of the church. As a place of worship, a place to meet, a place of authority and maybe even a little bit of intrigue in the shadows.
Event Background
Papal Palace throne room/main menu background illustration.
[With the addition of the Ecclesiastical government type, of course we had to add a new throne room background based on our 3D Papal palace.]
Building a great cathedral was a huge undertaking, spanning many decades until complete. With the addition of this Great Project we wanted to be able to reflect this in the event backgrounds as well.
Whether a big cathedral in the center of the city for all to see or a smaller (used lightly in this case) church at the edge of town, we wanted there to be more variations in event backgrounds with this DLC.
Of course we had to match the new church exteriors with some interiors as well. Here we tried to offer new options for all western churches, going from smaller, wooden churches to huge gothic cathedrals.
VFX
We also added a bunch of new event effects like light coming through the stained glass windows of your new cathedral, flickering candlelight, blurred vision and more! Special mention goes out to the new night shader which can turn any background illustration into night time.
When doing early concepting for the DLC, one of the first sketches that was done was a portrait type for saints. This was very much a collaboration between Tech Art and 2D UI. The halo was created by a 2D artist, then attached to the character model and additional light effects by our tech artist.
[Left: Saint portrait type concept. Right: Final in game version with added VFX]
UI Art
With the focus on Christianity we created a bunch of new Tenets to increase the flavor and allow you to customize your rite or personal faith even more!
With the reworked faith system which introduced rites, we needed a way to be able to differentiate them. It was easy to find references for crosses. In this case it was just more about the amount needed and the work that would entail that was the issue. To work around it a little bit we decided to make color variations to increase variety. But the main part of the task was simply: create as many Christian rite icons as you can within a week.
However, it was harder to find references for Islamic rites that we didn’t already have in game. Having to rely more on one shape like the Rub el Hizb but making variations of it that would work well as rite icons. Other inspirations included calligraphy, patterns and objects important to the faith.
All faith icons got color variations to be used as rites. Some even got a couple of new ones to increase variation, like Judaism, Hinduism and Jainism.
The faith panel has also gotten a revamp! With all the changes to faiths in By God Alone we rearranged the faith window to reflect this. You still have the regular faith stuff in there from before with a couple of updates and new icons. Tenet banners have also been updated to reflect the status relative to your mainline rite. This should make it more obvious at a glance if something is good or very bad.
The selection of a new Pope is one of the biggest events in the Catholic church and as an integral part of the church this warranted its own window. Visually we wanted to highlight the three top candidates and their supporters.
[Left: In game, Right: Early concept]
The Christian Church as a feature went through some iteration but eventually ended up as a situation which fit very well to the ever evolving/changing nature of the church. So this serves as a hub where you can see all the chapters, potential future chapters and the history as well as important decisions related to the church.
[Assets created for the Christian Church Situation using the illustrations made for each phase]
The Personal Beliefs window is the place where you can customize your personal tenets and see your Spiritual Fulfillment. This window has undergone some iteration but initially showed more of the illustration, showing the war between heaven and hell. It’s painted in this authentic style to the time, like it’s something you could see in a book or mural to make it fit more into the universe of CK3 without feeling too fantasy.
Puppets as a feature allows you to use other characters to make actions possible which wouldn’t necessarily be available to you without them. The feature itself has a very strong theme and inspired a lot with the making of the key art as well! The key art in turn inspired the icons for the different puppet types to use this carved, wooden style.
[Once you have a puppet, every time you right click on a character to interact with you get a tab with actions which you can act through your puppet.]
Animations
For this expansion we have added plenty of new animations to get that religious flavour across. There’s everything from various prayers and gestures, to preaching and whipping. We also added animations that describe characters' mental states based on their spiritual status.
[Mental Anguish]
Maybe feeling like you’re disappointing your god will make your character try to punish themselves?
[Self-Flagellation]
Once you’re back in the good graces of the church, you may get an epiphany…
[Divine Ecstasy]
[Two brains are better than one, showing the new Contemplation and Deliberation animations]
These are just a sample and you can find more than twenty additional animations added with By God Alone!
Domicile
The clerical domicile got updated with religious buildings to customize your clerical complex to fit your goals. Special for this domicile is that the main building actually requires you to build a Great Cathedral in order for it to level up.
Character Art
With By God Alone we added new character art including a wide selection of habits, cardinal vestments and additional clothing for higher tier members of the Christian church like mitres and copas. We also made new hair- and beard styles. The tonsures we added also have the positive effect of being affected by the balding trait, only giving it more variations on how it will show up!
[Above you can see a selection of habits, hair- & beardstyles and more variations of the habits which have both cloaked and uncloaked options for more variety.]
With the addition of the College of Cardinals we wanted to take this opportunity to create the cardinal vestments. These were only given to the senior members of the Catholic church.
[The iconic red vestments that make a cardinal stand out in any crowd]
We also wanted to create something more fancy by adding another robe and cape to that highest level of the pious.
No bishop is complete without its mitre. So we created two new ones, one early era and one late to cover the gaps in what we already had.
[In game and high poly close-ups of the new mitres. Top row: Early era, Bottom row: Late era]
Environment Art
Starting the Great Project to build a cathedral also adds a 3D model on the map at the chosen location. Below you can see the under-construction version and the three tiers for both Catholic and Orthodox cathedrals. Orthodox and Catholic share the Pre-Romanesque cathedral design as the first tier. These will evolve as the eras progress, roughly following the historical periods of Pre-Romanesque, Romanesque and Gothic cathedrals.
We also added new map buildings for other historical cathedrals.
[Lateran Palace]
[Palais des Papes]
[Reims Cathedral]
[Abbey of St Gall]
With the new DLC focusing on the Catholic church, there’s a lot of religious artifacts to take inspiration from! Croziers are a must for any high tier member of the clergy. We added five new croziers, varying in both level of detail and Catholic vs Orthodox.
[Any court of a true believer needs a crucifix]
[Ornate bible, when a regular bible just isn’t enough]
[Altar Cross]
[Situla and Thurible. These are also props being used in new animations. Swing for the fences!]
Playing as the pope requires a papal palace. So when planning to do this it felt like a no-brainer to reach out to ElTyranos. He not only made the gorgeous throne room for nomads in Khans of the Steppe, but also made a mod named “Aula Concilii (Lateran Palace) - Papal throne room” for Crusader Kings 3. A lot of research had already been done with this, but we wanted to up it to fit our three eras and have the throne room evolve with that, starting more simple and progressively being more and more ornate and decorated.
[Some of the references used make for layout and the overall feel of the throne room. This includes the Lateran Palace, Ravenna, Anagni and more.]
[Some nice details from the throne room. Early to late era fountains, candelabra, thurible and lectern]
[Era 3 stained glass window, mosaic decal and trims]
As CE3 deepens the core CK3 gameplay loop around Catholicism, our aim for music was to capture the dual nature of the Church: the "Divine Ecstasy" of spiritual fulfillment and the "Mental Torment" of sin and heresy. In terms of period and style we focused on Gregorian reforms through to the high medieval polyphony of the 12th century.
We commissioned Magnus Ringblum (once again), who delivered a brilliant sweet spot between the established CK3 orchestral aesthetic and Gregorian Chant and early Polyphony (Organum). Instrumentation was aimed at male choirs (monophonic and polyphonic), church bells, and acoustic medieval instrumentation (Fiddle/Vielle), while the atmosphere to convey was a mix of Grand/Regal for the Vatican, and darker textures for Heresy/Excommunication & Political Intrigue…
Mood tracks…
Anathema - representing the weight of Sin, more dissonant choral/organ textures, while still grounded in the origin of expected tone and texture.
Sanctos - “Divine Ecstasy” and the grandeur of the “Lateran Throne Room”, borrowing from Léonin/Pérotin influence.
The Conclave - capturing the “mayhem” of the political Church, inspired by the complexity of the Ars Nova (motet style), with interwoven voices representing the debate.
Cue tracks…
Council’s Judgement - covers two distinct outcomes set for the end of an Ecumenical Council. A little sinister undertone, judgement, meandering the unknown result (tonally).
Deus Hoc Vult - for the completion of “Grand Cathedral” Great Project, triumphant, a “Hallelujah” moment, full choirs and bells celebrating the architectural progression.
The Shepherd’s Flock - sets the scene for the state of Christendom in 876/1066, nostalgic but with a hint of political tension.
Outside of the literal music tracks, some specific stinger sounds in the expansion also borrow from the same musical themes and focus on representing the Christian Situation stability/instability and general growth/crisis. We treated these as quite literal representations of the different “feels” associated with each, building more dissonance and textures for instability/heresy, while aiming for more traditionally “whole” and audibly “rounded” phrases for the more positive/stable/celebrated moments.
Hello, I'm Saltfish, a designer at Studio Black - and a modder myself. I'll be walking you through the mod-friendly features you can look forward to in By God Alone. We considered moddability a key priority during development, and the result is a game that's more mod-friendly than ever before - from a fully reworked religion structure to dynamic holy sites and a brand-new puppet system.
This section focuses primarily on code changes, though we'll also cover some script changes that help you reduce the work of editing vanilla files. Thanks to our programmers, who have created a lot of useful features along the way!
Heads up: this section is about how modders can get the most out of the brand-new systems. It’s got nothing to do with content you can trigger in a vanilla playthrough. Be sure to keep that in mind when you read!
Rite and Faith
Our goal with the religion system was more granular control over how Rites interact with Faiths. To that end, most triggers and effects that work on Faiths now have a Rite-specific variant as well.
Move Rite
As you might have already guessed, yes - it's now possible to move a Rite to another faith via script, even across religious families! We originally only had this functionality for The Schism, but modders can now use it anywhere. I used this to create some... Interesting situations during modding.
[Prefer how Chinese religions are presented in EU5? You can use ! (The Divergence threshold can also be changed to any value, I set it to 300 to take this screenshot, otherwise they break away at once)]
Of course, you can also set a branch rite as the main Rite.
If you have read previous Dev Diaries, you might remember that Pope can declare a Rite as Heresy, and thus make it an independent Faith, it's detach_rite_to_new_faith
Disable & Enable Rite
You don't want to see Catholicism available in 867, right? A Rite can be disabled so you can't see it at all. You can also keep a Rite enabled but can't be converted to.
History of Faith
We introduced the history of Faith and rite. That means you can move rites, set Tenet status, disable or enable them. No more startup blob.
[During development, it was written in Rite definition, and caused many issues in modding (imagine if mods with new bookmark must override all Rites, otherwise constantly CTDs)]
Eventually, we came up with a different approach: you can declare a Rite active on a particular date, which automatically marks it as not created in bookmarks before that date. So you won't see it until it's enabled via script.
[Don’t ask why Carolingian is main rite after The Schism]
Structure
We now get all the 4 levels of religion (Rite, Faith, Religion and Religious Family) working "independently". You can add children without touching their parents. For example, now modders can declare a new Xinxue Rite under Confucianism, but in a new file instead of overriding Confucianism faith.
Also, you can now declare a Rite without a parent Faith, which makes it disabled and only available for script: then you can use create_rite_from_type to activate it as a Rite of given Faith. This feature would be useful if you want your small Rite mod to work with total conversion mods.
Everything about Tenet and Doctrine
Personal Tenet
There are some new blocks that mirror the Rite/Faith tenet system: can_pick, character_modifier, and parameter. Unfortunately we don't have on_pick_as_personal_tenet, but you do have on_personal_tenet_gain (and on_personal_tenet_loss).
Triggers
You don't want to pick a syncretism tenet that tolerants you in an Ecumenical Council, right? So we get (rite_)can_choose_tenet/doctrine. It works as if editing or creating a Rite based on current status.
Effects
We've added change_doctrine, which automatically replaces the existing doctrine in the same group - making life easier without having to list every existing case to remove.
Structure
As with the four-level religion structure described above, you no longer need to override anything in the religion folder for adding Tenets and Doctrines! With these changes, the incompatibility of the religion system when adding new content is greatly reduced.
Tenet name/desc/icon are defined at the Rite level, while other blocks (excluding personal tenets) remain at the Faith level. All of the flavorization of Doctrines are also at the Faith level.
You can define a Doctrine in a Rite/Faith/religion lock, which means it's automatically removed if the Rite changes Faith/religion (in combo with set_parent_faith), or creating a new Rite/Faith based on the Rite with that Doctrine.
Clerical Region
It's a dynamic region as you can see in previous Dev Diaries, and is bound to a clerical title, a new type that can be checked. I know some of you will hijack it for other purpose like military region, transport region, monitor region... Or sphere of livehouses, it’s fine, no problem.
From modding perspective, you can:
Add/remove counties to/from a region
Split/merge/create a region
The domicile is bonded to the clerical region, which means, unlike other Domicile titles (they accept government), create_clerical_region accepts domicile_type as input.
Holy Site
Yes, a fully dynamic holy site system! You can create brand new Holy Sites, adopt holy sites from other Faiths (note: this is at the faith level, not the rite level), or abandon them. This means the old deactivate/activate Holy Site system is a thing of the past.
Each Faith/religion has independent max Holy Site limits (with default max/min in defines), plus an optional major Holy Site at the religion level that can't be demoted or removed. If you want... you can steal every holy site of the world.
Note that the limitations above are purely script-based. You can use script without checking the number to exceed them, if you so desire.
Saint (or ancestors etc, based on your religion)
It's more script but there are some code features worth mentioning: Saints are linked 1 to 1 to provinces with holdings (so you have event target link); there is a counter for how many relics you can extract (relic itself is purely script so you can abuse the counter as magic power etc).
Saints are at Faith level (not Rite, again), and you can remove them.
We also introduced some more flags here, for example, to hide the Tomb of Saint Mary (QA team expressed strong concern when they saw Virgin Mary's body was still “buried” in Jerusalem) or stop extracting body parts of a mummy or from someone who died in an unknown place. (You know, taking relics is very Christian behavior, in most religions it’s profane to take part of a corpse, so we get a set of different “Relics”, from paper to accessories, for different religion/Tenet/Doctrine, and those non-body Relics become fallback when no corpse is available)
HoF challenger (i.e. Antipope)
If you are in a realm with a challenger, most of your HoF interactions will be redirected by religious_head_or_challenger - except papacy/cardinal interactions since challengers do not have their own college of cardinals.
A Faith can have multiple challengers, and a challenger has a sponsor. Both challenger and sponsor are titles to be passed through successions.
Puppet
Puppets need puppet actions to work, most are interactions, with some great projects and decisions, and a tiny bit of trigger action.
All of them can have a valid block that is only available when the check returns true.
Interactions
By using scope:puppet_or_actor in interactions you can allow most interactions. Here scope:actor always exists, referring to the puppeteer when used in puppet interaction.
Note that is_available, as well as other blocks that implicitly use root, are still based on the actor.
To check if an interaction is run by a Puppet, use scope:is_puppet_action ?= yes
We replaced many scripts of interaction, to make some interactions usable for puppet, despite not all of them being used as puppet actions in the vanilla game. (I swear I just wanted to reduce modding replacing work. But other designers used some of them in vanilla. And then we found the script was not fully replaced, so we spent some more time fixing them… Sorry to my colleagues for simply replacing those XD)
You ask why most interactions, not all, support the puppet system? If you're familiar with interactions, you'll know that some are special — they need code input. For example: declare war, grant/revoke titles, modify contracts (you can try this: the game refuses to open the modifying contract window if actor and recipient do not have correct overlord/subject relationship) etc. However, our programmers made time to support declaring war interaction, and then I personally learnt how to add support myself for other functions by mimicking their work. Just like the way we learn modding.
[Grant/revoke titles as puppet interaction are balance breaking in vanilla, but we left the possibility to mods]
Decisions & Great Project
When I wrote this, only interactions had GUI function support for selecting which puppet, if any, was used. So if you have access to the decision or great project by yourself (judged by is_shown), you can't select a puppet to do so. You might need to write a proper script trigger to make this understandable and easy to use.
We are looking to plan corresponding supports for the .1 patch, though this is still under review and remains subject to change.
Trigger Actions
Unlike other puppet actions, this type is a script trigger: not directly linked to any interaction, decision or project. For example, in vanilla, it's used to explain that you can vote in an Ecumenical Council, or decide if you can create a new Rite.
DYNAMIC DECISION OPTIONS!!!!!
Like EU5, you can pick any scope type (and build the option list by yourself) as options in decisions. In vanilla we use this to pick saint candidates, Holy Sites, Heresy Rites, Tenets etc. Please notice that if you are using a new scope type, you might need to duplicate a controller GUI for it.
Hello everyone! My name is Edward, though you may know me around the community as Uber, or now PDX-Uber. I’m the User Generated Content (UGC) Creator Manager for our Grand Strategy Games here at Paradox Interactive, and today, alongside our wonderful UGC Engineer, PDX-CrimsonKepler - I’d like to introduce our UGC Experience (UGCx) Team and give you a brief rundown of the work we’ve been doing to support modding in Crusader Kings III so far!
This initiative started late last year and really picked up pace in April of this year. We’ve already been sharing some of our work in smaller modding spaces, such as the CK3 Mod Co-op, but this is our first opportunity to properly introduce ourselves and what we’re doing to the wider CK3 community.
Our goal is to make modding easier to get into, easier to learn, and easier to build upon, while also enhancing the player UGC experience by making it easier for players to find, install, and manage mods for CK3. PDX-CrimsonKepler is helping us achieve this by expanding and improving modding support in collaboration with the CK3 development team.
The CK3 Creator Program
A big part of this work happens through the CK3 Creator Program, a dedicated space where mod creators work closely with us, the wider UGCx team, and our colleagues on the Development and Community teams. It gives creators a direct line to discuss their projects, raise issues, and help us understand which tools, fixes, and mod-support features would make the biggest difference.
Creators in the program work on everything from smaller vanilla+ mods to some of CK3’s largest total conversions. Working closely with them has deepened our understanding of their goals and the limitations they face. Their feedback helps inform our priorities and the improvements CrimsonKepler has been working on. Some of the results of that collaboration are what we’re here to share today!
Hi, I’m CrimsonKepler, the UGCx team’s UGC Engineer, which is fancy speak for “modding programmer”, working on Crusader Kings III. My job is to write code to make more things in the game moddable, make the things that are moddable easier to mod, and make creating compatible mods possible for a wider range of features.
Within the Creator Program, I discuss with modders what changes could be most useful and how an improvement should be implemented to be most usable. Sometimes I even discuss how to best implement an improvement with modders, while I am in the middle of writing the code for it.
Having a dedicated role of specifically writing code to improve modding means that the technical hurdles of certain long-requested improvements can now be given a proper investigation. One of those is the request to be able to override the definition of single events without having to replace the entire file, a major problem for mod compatibility. This could not be implemented like the existing overrides, which rely on load order. The contents of the files in the events folder are parsed and loaded in parallel, so their load order is essentially random. The solution? Giving modders a tool to explicitly set their event definition as higher priority than vanilla, regardless of the load order.
As we collaborate with the modders in the program, we focus on making improvements that are useful for many different mods, since the improvements are intended to benefit the wider modding community. A limitation raised by a total conversion team might also affect someone making a much smaller mod, and addressing it can open up possibilities for both.
Thank you to the creators who have been sharing their experiences, raising issues, and helping us shape this work. There’s plenty more we want to do, but today we’re excited to share some of the results so far.
With introductions out of the way, let’s take a look at some of the modding improvements coming in the free update alongside By God Alone! In addition to the improvements and additions listed below, I’ve also fixed plenty of bugs found along the way or reported by creators in the program.
# **User modding:**
Single Event Override: Added id_override_priority property to events, which allows overriding an event without having to replace the full file.
Added grandchild and great_grandchild character lists
Added real_parent, real_grandparent and real_great_grandparent character lists
Added on_trait_gained and on_trait_lost on_actions
Added effects for removing parents: clear_father, clear_mother, clear_real_father & clear_real_mother
Added on_character_created on_action that fires whenever a character is directly created, as opposed to born
Added triggers days_since_birth, birth_date, day_of_year_of_birth, month_of_year_of_birth and day_of_month_of_birth
Added on_liberation_siege_completion on_action
Added `set_faith_name` and `set_rite_name` effects
Made the reason for death be passed directly to `on_death` on_action as a scope!
Added `on_player_character_change` on_action
Added `create_domicile_title` effect, which allows you to create a dynamic title with a domicile, not tied to any vanilla government type
Added scripted rules `can_create_title` and `can_destroy_title`
Made `has_court_position` trigger able to take a scope
Made `court_position_holder` script lists able to take a scope for the court position type
Added ability to perform single character override in history
Added `effect_even_if_dead` for character history
Massively reduced bloating of error log caused by having save games from incompatible playsets
Made adding new doctrines not require changing the doctrine group file for its group
Made adding new laws not require changing the law group file for its group (there are now separate files for laws and law groups)
Made `rivers.png` hot reloadable.
Finally, a modding feature not done by the UGCx team, but by the wonderful hardworking tech-programmers of the CK team:
Expanded accessory gene index limit from 255 to 2,147,483,647.
Hello folks, Mikael here! If the promise of eternal salvation is insufficient for you, I hope you'll be pleased to hear that By God Alone will also let you vie for some new achievements. These are of course related to all the new mechanics we've added, such as Personal Tenets, Puppets, Playable Theocracies, Ecumenical Councils, Holy Sites and relics, and the College of Cardinals. A couple of them you might earn in the process of everyday play, but most of them you'll have to labor for. Quodcumque facere potest manus tua, instanter operare (Ecclesiastes 9:10).
[The ten By God Alone achievement icons in a row]
Easy
Holier Than Thou - Have three Personal Tenets and 100 Spiritual Fulfillment at the same time
Find a way to adopt not one, not two, but three Tenets into your daily practice, and adhere to them so hard your Spiritual Fulfillment climbs to the cap. If you took Asceticism as a Gluttonous king this could take a while. If you'd rather be efficient about it, the Personal Faith view will tell you exactly which of your traits is dragging you down and which Tenet is doing the heavy lifting, so you can rub your humility in everyone's faces!
Medium
The Father, the Son, and the Holy Grandson - As a Theocrat, establish a Dynasty and hold an Archbishopric for three generations
Take the Establish a Dynasty decision as an Archbishop, then make sure the next holder of your See is one of yours, and the one after that as well. We went over why that's hard in the Puppets and Theocracies diary: most of your candidates will be sworn to celibacy (unless the Church gets very, very weird in your playthrough) so "generations" here means nephews, protégés, and whichever bastard you happen to be aware of, mentored and elevated in time to be at the top of the appointment shortlist when you die.
Where There's a Will - Demand Church Succession from another ruler, then murder them and inherit their lands
Demand Church Succession is a new interaction for landed clergy. Find an elderly secular ruler of your faith with no living children and have it agreed that, should they pass without a rightful heir, their realm falls to your title as fallback. This is a perfectly respectable piece of medieval estate planning; bishoprics grew fat on it for centuries. The only disreputable twist is that of the knife in their back at the end.
Home See Advantage - As an Archbishop, change a tenet or doctrine at an Ecumenical Council hosted in your own Cathedral
Ecumenical Councils are where the faith settles its many, many emergent differences of opinion. The Pope sometimes calls them, but an Archbishop can host one too. Host it in your own Cathedral See, with your own clergy filling the pews, and when one of the debates you care about actually passes, that's the achievement. Home crowd, home rules. The Pope is welcome to attend, but is not obligated to enjoy.
Cardinal Sin - Starting as a non-Clergy ruler, have five members of your dynasty as Cardinals at the same time
Cardinals are appointed by the Pope, so getting five of your own dynasty into red hats at once means either a Pope who owes you a great deal, a family that keeps producing suspiciously well-qualified bishops, or both. It also needs a College with enough room to fill - and in 867 that institution is still finding its feet.
Father's Best Side - Enshrine a relic taken from a saint of your own family in a Holy Site your Dynasty founded
First you need a saint in the family, which means someone of your house has to die devoted enough to be canonized. Then you need a Holy Site your dynasty created rather than inherited or adopted. Enshrine the one in the other, and reap the rewards.
Hard
Guido's Guiding Light - Starting as Archbishop Guido of Milan, become Antipope and make the Ambrosian Rite the mainline rite
Our one character-specific achievement. In 1066 Guido da Velate has held Milan for twenty years, is on famously bad terms with the reform party in Rome, and presides over a liturgy the city has kept its own since Saint Ambrose. In our version of events he stops apologizing for it. Proclaim yourself Antipope, or find a sympathetic Emperor to proclaim you, then win the argument so completely that Rome ends up celebrating Mass the Milanese way. For the record, the Ambrosian Rite still has millions of followers today, so it's not that hard to imagine.
Servus Servorum Dei - Starting as a Duke-or-lower secular ruler, or a Count-tier cleric, become the Pope
"Servant of the servants of God" is the title Popes give themselves. This is meant to be a "Rags to Riches" type achievement, so you need to start small. A count or duke needs to get someone of the house into the clergy and play on through them, while a Prince-Bishop starts with the collar already on but a very long way from Rome. Either way the route runs through the Cardinals diary: earn a red hat, sort yourself into the right voting bloc, and be the candidate the swing votes settle on when the old man dies.
Papal Bull - Make your Puppet Pope sleep with your spouse
Before you begin, make sure you have secured in your possession: a means to make the Holy Father Himself your Puppet; a spouse; and a cunning, sordid plan. With respect to any prospective future heir of yours, any resemblance to actual Popes, living or dead, is entirely coincidental, I'm sure.
I want to be clear that several people of legal drinking age and allegedly sound mind have somehow been persuaded to sign off on letting us publish this achievement.
Very Hard
The Two Swords - Have both the Holy Roman Emperor and the Pope as your Puppets at the same time
Medieval theorists liked to say God had given the world two swords, one spiritual and one temporal, and then spent several centuries arguing about which hand held which. But what if both could be yours? Hold a Hook on the Emperor and a Hook on the Pope at the same time, puppet both, and revel in your newfound freedom. Keep in mind that Hooks expire, Popes die, and Emperors get elected - keeping both leashes taut for long enough is going to be quite a challenge.
[Achievements of By God Alone with the difficulty tiers]