The Reincarnation

S1, E1: In a distant world, Shagurua, the hero known as the Calamity Crusher, battles a necromancer without peer known as the Corpse God in order to save the world. After a fierce battle, just when Shagurua appears to have defeated the Corpse God, a magic is activated, surrounding the area with light. At that moment, the soul of the Corpse God is transferred to a faraway world, and he wakes up in modern Shinjuku in the body of a young boy, Polka Shinoyama, who had just been murdered. As he wanders around town in the body of Polka, he is rescued by a girl who calls herself Misaki Sakimiya. Upon seeing her, Polka's memories gradually return.