Having lost his mother and sister, Hatamata Souma led a life of carnage and violence. One day, he was summoned into a world where spirits and magic existed. “You shall be offered up as a sacrifice to the Great Water Spirit to stop this rain.” Beaten and sunk into the lake for this unreasonable request, Souma came to face with the Great Water Spirit Izan. There, he learnt that his missing sister was also summoned as a sacrifice and died. As atonement for the collapse of Souma’s life, Izan bestowed to him the power of the great spirit. Now with the ability to control over water at will, Souma vows to exact revenge and eradicate summoning magic from this world. Thus, he lives on as the great wizard Souma who lost his memories, however—. Source: Shufunotomo