If you've played Guild Wars or its sequel, you'll know that the land Tyria is a godless place. It didn't used to be, but more than 1200 years before the events of the original 2005 MMO, the gods upped sticks and abandoned the planet, leaving the different guilds their own devices. As the series' name would suggest, those devices were largely swords and siege weapons.
In looking for a good spot in the series' timeline to set a new game that would be as alien to people who have played the games for the past 20 years as those who have never set foot in the land of Tyria, developer Arenaet have settled on the moment the gods decided to leave.