The ending to the third Assassin’s Creed game was originally intended to end quite differently, according to interviews with staffers that worked on the titles and conducted by a Ph.D. student.
In a paper written by Lars de Wildt, who researches conspiracy theories, religion, and other beliefs in digital media culture, the original ending to Assassin’s Creed 3 would have seen Desmond and Lucy leave Earth on a spaceship – the plan being to continue the human race elsewhere after the end of the world in 2012. Like a modern-day Adam and Eve.
Instead, things turned out differently. Lucy died in Assassin’s Creed: Brotherhood, and in Assassin’s Creed 3, Desmond sacrificed himself to protect the planet from a solar flare that would have caused the Second Disaster.