[quote=@Ariamis]
Is this humans only? No aliens or cyborgs for example?
[/quote]

Minor cybernetics possibly, but nothing weaponized. The ship would have had really strict laws in place. Of course, where the story starts, there won't be any more law, so that could change. Aliens I can run with, but we'd have to discuss that in depth over PM.

[@WilsonTurner] - With what I had in mind, most of the population would know they were on a ship. I wouldn't recommend being part of the ship's crew because you would start apart from everyone else. Part of the party's goal would be to access the Grimoire's bridge, but they have no idea where that is, and the Ecospheres they live in are hundreds of thousands of square miles, so they would need to travel for a long time. You can be an ex-mechanic, though, or even a crew member on vacation. As long as everyone starts in roughly the same vicinity, for the sake of convenience.