The Keeper of Night by Kylie Lee Baker

I am too dangerous to let live any longer.

It is written in the Book of Ankou, decreed by the High Reaper himself.

Death will come to find me...but I will no longer be there.

Half British Reaper, half Japanese Shinigami, Ren Scarborough has been collecting souls in the London streets for centuries. Expected to obey the harsh hierarchy of the Reapers, who despise her due to her mysterious mother and even more mysterious Shinigami powers, Ren conceals her emotions and avoids her tormentors as best she can.

When her failure to control her developing Shinigami abilities drives Ren out of London, she flees to Japan in search of the acceptance she's never gotten from her fellow Reapers. Accompanied by her younger brother, the only being on earth to care for her, Ren enters Yomi, the Japanese underworld, to serve the Goddess of Death...only to learn that here, too, she must prove herself worthy.

Determined to earn respect, Ren accepts an impossible task -- find and eliminate three dangerous Yokai demons. With help from only her brother and a new ally who might be less than trustworthy, Ren will learn how far she'll go to claim her place at Death's side.