After a series of attacks from Muzan, Gyomei comments on how he appears to be getting faster, so fast that the Mitsuri barely manages to dodge his attacks on pure intuition and luck.
Mitsuri, before she can land an attack, realizes that she's getting dragged down by one of Muzan's arms. Another attack from him manages to slice some of the Hashira's right cheek off and injure the shoulder of her right arm. Obanai jumps to rescue her, and with the help of Sanemi, Giyu and Gyomei holding Muzan back, he's able to carry her to another Demon Slayer.
He commands him to find Yushiro to treat her injuries and the Slayer agrees. However, Mitsuri insists on keep fighting but Obanai doesn't allow her. As he leaves her, she pleads him to not die.
Obanai, as he's running contemplates the number of people that have died, all because of the existence of demons. At first, wishes that he and Mitsuri had met under normal circumstances, but takes it back saying that he would rather die (after killing Muzan that is) and cleanse himself of the filthy bloodline he carries within him. His bandages, fall behind him as he's running to reveal slits across his cheeks.
His family stole money and lived a luxurious life from it. Obanai was the first male born in the clan in over 370 years and was confined to a cell because of this. He would have died earlier if it wasn't for his heterochromia, as the demon living there (who ate offsprings in return of the humans living there), with the lower body of a serpent, decided that he should grow a more satisfying size before she'd eat him. She was also the one who ordered the other females of the clan to cut the sides of his mouth to resemble her.
During this, Obanai manages to steal a hairpin and was able to slowly cut away the wooden cage with it and escape, Kaburamaru, strayed inside the cell before their escape. Because of him, the serpent demon killed everyone else in the clan, and tried to kill Obanai but Shinjuro Rengoku, the Flame Hashira at the time cut her head off, saving Obanai and his female cousin, who threw a fit at him.
By becoming a Demon Slayer, he felt as though he became a better person, even if the souls of the dead family members always dragged him down.
Obanai restates that he would like to die by killing Muzan to purify his blood and hopes to meet Mitsuri again in another life without demons if he and her are ever reincarnated into humans, and, if that happens, he'll confess his love to her.
Characters in Order of Appearance
- Muzan Kibutsuji
- Gyomei Himejima
- Obanai Iguro
- Giyu Tomioka
- Sanemi Shinazugawa
- Mitsuri Kanroji
- Shinjuro Rengoku (flashback)
- Obanai's backstory is revealed.