Hi everyone!
First of all, thank so much for your interest in Welcome to Empyreum 🩵
We'd like to kindly remind you that this game is designed for local multiplayer and does not include an online mode. However, it is fully compatible with Steam Remote Play Together, which allows up to 4 players to enjoy the game over the internet using just one copy.
Using Remote Play Together is super easy: the player that owns the game just needs to launch it and then invite their friends to join the game with an invite link or through their Friends List. You can find more information about this feature here.
We apologize if it wasn't clear enough that Welcome to Empyreum only supports local multiplayer, and we hope that you keep enjoying the game.
Thank you!