Last year, CD Projekt revealed that they are not only working on a highly anticipated sequel to The Witcher 3: Wild Hunt, but also have several other projects in the works. At least one of them looks to be co-op and PvP, at least if it is to be believed job ad which is now out, where the developer The Molasses Flood, now part of CD Projekt is looking for someone who has experience designing multiplayer and co-op.
The fact that The Molasses Flood is mentioned suggests that it is the game that only goes by the code name “Sirius” that is being referred to. There is currently no other official information about the project, neither story-wise nor technically. The only thing that is known is that it is set in the Witcher universe, that The Molasses Flood is developing, that it will not be a mobile game and now we can most likely add that it will have some kind of multiplayer.
