Kamo: Pact with the Spirit World, Volume 1: Pact with the Spirit World - Kamo: Pact with the Spirit World manga

"Born with a failing heart, Kamo has fought death his whole life, but to no avail. As his body weakens and he readies to draw his final breath, he's visited by a powerful spirit named Crimson who offers him a deal: defeat and capture the souls of twelve spirits in exchange for a new heart. It seems too good to be true and maybe it is"--