Obanai is the Serpent Hashira, he created Serpent Breathing derived from Water Breathing. He is very harsh, strict, and has high expectations for other slayers. He has extreme hatred for women or gynophobia due to his traumatic past with his family, but Mitsuri is exempted because he has a crush on her. Gets extremely jealous when someone gets too close to Mitsuri. He's on good terms with Sanemi, while they both hate Giyu. He always has an albino snake on his shoulders, it's name is Kaburamaru.