It is strange that the two games are coming out at about the same time.
However, Sacred is significantly different. Unlike beyond divinity which is sort of ultima diablo, sacred is more straight Diablo. PEople on this board obviously like DD, but thats not what sacred is trying to be.
So for the people bored by the conversation strings in DD might like it more.
Im not sure how close to the actual game the demo is. The demo itself wasnt very entertaining to me, but it looked great. Im likely to get both games.
Sacred has multiplayer also. I think its going to be a lot of fun.
