Blue Exorcist - S05

Rin Okumura, unlike his twin brother Yukio, never cared much about their parents or the details of his birth. But when the time-manipulating Mephisto Pheles hands him a key, Rin is sent 40 years into the past, where his late mother, Yuri Frederick Egin, is still a child. Guided by Mephisto, Rin jumps through key moments of Yuri's life-her childhood and her training as a young exorcist. Early in his journey, Rin sees Yuri meet Shirou Fujimoto, the man who would later become his and Yukio's adoptive father. As Rin observes Yuri and Shirou's lives unfold, he witnesses the first signs of Satan's influence-his real father-and the dark events taking place within Section 13 of the True Cross Order. Through Yuri's strange bond with Satan, Rin uncovers the truth behind the Blue Night, the most infamous tragedy in exorcist history and the night he and Yukio were born.