One of the main writers of the Assassin’s Creed series Darby McDevitt gave interview portal Axios and talked about how the endings for some projects of the series (Revelations, Embers, Black Flag) were created and what was not included in the original plans.
In 2014, McDevitt assisted the developers of Assassin’s Creed: Unity with lore writing and database creation. Then the scriptwriter had an idea how to connect the game with the future project of the series (Origins).
The protagonist of the game Bayek had to hunt 12 Templars who were captured by the “souls” of the Egyptian gods. These 12 gods were mentioned by Juno as the “Hidden 12” in one of the Unity database entries. Interestingly, it was also mentioned that Desmond Miles, along with Subject 16 (Klay Kaczmarek), are alive and in “Gray”. We can say that the screenwriter partially embodied one of his ideas in Valhalla.
Unfortunately, after the release of Unity, the idea with 12 gods had to be abandoned, but Darby McDevitt himself, who recently returned to Ubisoft (and seems to be working on Assassin’s Creed: Rift), does not mind rehabilitating this unsolved story in the future.