Shinigami no Yaiba.

Jiro Kanbara (Yasukaze Motomiya) is a washed-up low-level thug who has drifted into his mid-thirties without ever getting anywhere. One day, he is ordered by his boss (Tomorowo Taguchi) to assassinate Onijima (Hitoshi Ozawa), a key figure in a rival organization—and he carries out the hit. But the man he killed and buried suddenly appears before him again. It seems Jiro has been possessed. Onijima’s voice whispers in his ear, guiding his every move. As Jiro follows those instructions, his fortunes change dramatically—he rises rapidly in the yakuza world, gains status, attracts women, and begins living a life just like Onijima once did. However, such a life cannot last forever…