Platinum End

When life becomes too much for Mirai to bear and attempts taking his own life, he’s saved by Nasse, a guardian angel who offers him a chance at becoming the new god. To do so, he must face off against 12 other candidates within 999 days. Mirai, who was once at rock bottom, now finds himself with supernatural powers in a battle royale for the highest title.
(Source: Funimation)