The only reason I picked that model is because it was the only free and halfway decent-looking humanoid model in the Unity Asset store. I would have preferred something looking a bit more like a monk but well, there isn't a lot to choose from when you're on a budget :D
The screenshots here are a little bit outdated as well. In the actual game itself you'll notice that the librarians have a completely black shader applied to them, which makes them look more like mysterious 3D shadows rather than creepy monsters out of a bad horror game.