According to the Steam page for this game, it is not compatible for Windows 10, and there's no telling if it will ever be. Ubisoft likely doesn't care that much.
Screenshot from Assassin's Creed Revelations Steam page:
Perhaps try running the application in compatibility mode for Windows 7. To do so, find the AC-Revelations folder in your Steamapps location, then:
- Right click the executable for the game, and select Properties
- Find the compatibility tab, select "Change Settings for All Users"
- Check "Run this program in Compatibility Mode"
- Choose Windows 7 SP1 from the Drop down
And try it again. If this does not work, @pushasha's comments may work. Otherwise, there may simply be no hope, as compatibility to Windows 10 is tricky.
systemdetection.dll
from the game folder has helped people for whom the game was crashing.