Tōshirō
Hitsugaya

Toshiro Hitsugaya is the youngest captain in Gotei 13 history, a prodigy from the same icy district Rangiku Matsumoto found him in, permanently annoyed at being treated like a child and permanently doing his paperwork anyway. His Zanpakuto, Hyorinmaru, is the strongest ice-type in Soul Society, and his Bankai, Daiguren Hyorinmaru, wraps him in wings of ice with petal counters that track how long he can hold it, a detail the show uses to remind you he is not finished growing.

His defining wound is Momo Hinamori. They grew up together, she worshipped Captain Aizen, and Aizen's staged death was arranged to point her sword at Hitsugaya. When Aizen's betrayal finally surfaces, he runs Momo through and then compliments Hitsugaya's rage before dropping him too. In the fake Karakura Town, Aizen tricks Hitsugaya one more time into stabbing what he thinks is the enemy and is actually Momo. The series has never fully let him put that down.

The Thousand-Year Blood War is his gauntlet. Cang Du steals his Bankai and Hitsugaya fights on with ice-flower tricks until Urahara's shin'eiyaku lets him take it back. Then Giselle Gewelle kills and zombifies him, and the Gotei 13 gets to watch a zombified Hitsugaya maim Ikkaku and Yumichika before Mayuri reclaims his corpse with a drug that trades lifespan for freedom. He comes back anyway. By the Wahrwelt invasion he is on the walls with Rangiku, alive, restored, and colder than ever in every sense the show intends.