Tatoe Hai ni Nattemo

Ryouma needs one billion yen for his terminally ill sister--but instead of a loan, he loses his life! Now he's stuck in Limbo with a sadistic angel named Kroel and four other victims of fate. If he can gamble his way to the top, he might just escape with both his life and the money he needs to save his sister. But if he fails, it's ashes to ashes, dust to dust--for all eternity!
(Source: Yen Press)
Note: This manga was canceled after the author passed away.