Jigokuraku 2nd Season

A deadly ninja, Gabimaru, once known as the Hollow, has no fear of dying and has committed many assassinations. After all this, he lost his hope to live anymore, and he was later sentenced to death. All the people who try to kill him fail, but then Saigi, a young executioner, is sent to kill him. He wasn’t ready to die, but Sagiri somehow knew his will to live with his wife. Sagiri promised to set him free if he was able to bring the Elixir of Life from the Shinsekyo island. He accepted the mission and set out on his journey to the island of death.