Shin Samurai Spirits

Overview

The story begins with Hanzo Hattori checking on his comatose son, Shinzo. Although he knows that his son's body is alive, Hanzo laments his powerlessness in saving his son's soul. While he prays for his son's revival, Shinzo's soul flickers into his body. He tells his father that Amakusa's soul is still alive in the Makai (demon world), begging his father to stop the villain. Moments later, his soul is struck back into the Makai by Amakusa, once again leaving Shinzo's body lifeless. Enraged and in grief, he leaves to try and get his son's soul back.

Source: AniList