In the human world "Assiah", life reproduces and resembles; in another hellish dimension "Gehenna", there are demons living in it.These two worlds should not interfere with each other, but the greedy and evil monsters have repeatedly crossed boundaries, occupied the world, and possessed themselves on the living, causing chaos and disaster.Those who can fight against these demons and protect the peace of the world are called exorcists. Rin Okumura, a cursed boy born, carries the fate of Satan's illegitimate son.His adoptive father, a true exorcist, gave his life to protect him during the demon attack.At that moment, the flames swallowed up faith and family affection, and also ignited the anger of revenge in Rin's heart.In order to avenge his adoptive father, and to prove to the world that even with demonic blood flowing, he is qualified to be the light to protect others.Rin resolutely embarked on the path of becoming an exorcist and headed towards the path of fate that intertwined with light and darkness.