Why Han't this been named yet? Kamigami No Asobi is an awesome game(along with an amazing book and show). It includes a nice selection of characters or should I say Gods, from different religions. You play as a human girl who was chosen by Zeus (the Greek god) to attend a school with 9 gods and teach them about Humans and love. You have one year to help them graduate or else you cannot return back to your world. But its not timed or anything so don't worry. I highly recommend this game. There is no English patch of the game but there is a translation:
http://sweetremiks.tumblr.com/kamiaso

Other than the game there is, as I said above, a show/book which is just as good (well almost as good in my opinion) as the game itself.

Also I just want to point out that Hades is voiced by Sebastian Michaelis from black butler, the Japanese version.