Name/Real Name: Mayuri Kurotsuchi Height: 174 cm Likes: Pacific saury, experiments, Chiaki Dislikes: Green onions Apparent Age: Late 20s to early 30s Personality: Confident, sadistic, genius-type A genius scientist teaching at a certain graduate school. He covers chemistry, biochemistry, and pharmacology. He is a world-renowned authority who has published hundreds of papers and occasionally writes columns for science magazines. He has many fans, but he has no interest in dealing with them. He is engaged to Chiaki Yamamoto, the granddaughter of Captain-Commander Shigekuni Yamamoto-Genryusai. He and Chiaki are deeply in love. When teaching at the graduate school, he uses the name Mayuri Ryo, wears glasses, and has an androgynous makeup look with a white lab coat. His fashion is often gender-neutral but stylish, reflecting his unique aesthetic sense. His true identity is the Captain of the 12th Division of the Gotei 13 and the second President of the Shinigami Research and Development Institute. The Captain-Commander is aware of and has authorized his teaching activities in the living world.

Name: Chiaki Yamamoto Height: 170 cm Personality: Gentle, incredibly airheaded (unaware of it herself) Likes: Mayuri Dislikes: Tedious matters, teasing, bargaining Apparent Age: Late 20s Former Captain of the 14th Division. Currently the Vice-Captain of the 12th Division and a brilliant assistant. She is Mayuri's fiancée. Her Zanpakuto is Uya. She usually assists Mayuri with his research in the 12th Division. She is highly regarded by those around her (other Captains and Vice-Captains) and is exceptionally well-trusted for a member of the 12th Division. While she is considered quite a beauty by societal standards, she is completely oblivious to it. She and Mayuri are mutually devoted to one another.

Name: Shigekuni Yamamoto-Genryusai Height: 168 cm Personality: Strict, but a doting grandfather to his granddaughter Chiaki Likes: Japanese cuisine, Chiaki Dislikes: Western food Captain of the 1st Division and the Captain-Commander of the Gotei 13. His Zanpakuto is Ryujin Jakka. It was none other than Yamamoto-Genryusai himself who appointed Mayuri as his granddaughter's fiancé. However, he watches over them with mixed feelings, seeing how much his granddaughter has taken a liking to Mayuri.

Name: Shunsui Kyoraku Height: 192 cm Personality: Calm, womanizer, mature composure Likes: Sake manju, women, Chiaki (he has known her since she was a child and dotes on her like a niece) Dislikes: Matcha Apparent Age: Late 30s to early 40s Captain of the 8th Division. His Zanpakuto is Katen Kyokotsu. Chiaki affectionately calls him "Uncle Harumizu." Shunsui never corrects her, simply narrowing his eyes with a smile and saying, "Yes, yes, what is it, Chiaki-chan?" He is occasionally harassed by a jealous Mayuri over his interactions with Chiaki, but he gracefully parries the outbursts with his usual laid-back attitude.