Platinum End, Vol. 1 — Tsugumi Ohba

As his classmates celebrate their middle school graduation, troubled Mirai is mired in darkness. But his battle is just beginning when he receives some salvation from above in the form of an angel. Now Mirai is pitted against 12 other chosen humans in a battle in which the winner becomes the next god of the world. Mirai has an angel in his corner, but he may need to become a devil to survive.