Scuro

Rayet, codenamed Scuro, works as an assasin for the infamous group Scarlet. His soul job is to assassinate other assassins as part of the "clean up team". Sick of taking lives, Rayet attempts to leave Scarlet. With the help of a fortune teller named Juki and his assistant Ritsuna, Rayet may just succeed. However, Scarlet doesn't intend to let him leave alive.
(Source: M-U)