Angel Sanctuary (Angel Sanctuary #5)

Setsuna Mudo is a mixed-up high school student who has gotten on the wrong side of God. He is the reincarnation of an angel who has rebelled against heaven. Now the Angels want him dead, the demons want him to lead the revolution, and he just wants a clue to how the world works.

Setsuna has seven days to find his beloved sister Sara in the afterlife, and the first stop is to find the Guardian of the Hellgate - a being any normal person would avoid! Kato, an old enemy of Setsuna's, is now his only companion, but Kato has a history of being manipulated in life. Now that he's dead at the hands of Setsuna himself, just how far can he be trusted?