WARNING: The following contains spoilers for Demon Slayer: Kimetsu no Yaiba Season 2, Episode 12, "Things Are Gonna Get Real Flashy!!," now streaming on Funimation, Hulu and Crunchyroll, as well as spoilers for the Demon Slayer: Kimetsu no Yaiba manga by Koyoharu Gotouge, available in English through VIZ Media.
Tengen Uzui was a little difficult to like during his introduction in Demon Slayer: Kimetsu no Yaiba's "Entertainment District" arc, given his treatment of the women at the Butterfly Mansion. Belittling Kanao, tossing Naho to the ground and slapping Aoi on her behind gave the impression that the Sound Hashira has no regard for anyone else. Surprisingly, the events in the Entertainment District have made it clear that Tengen does indeed have a heart. In fact, given what has been revealed about Tengen in the anime as well as information about his past from the manga, the flashiest Hashira just might have the biggest heart of anyone.
When Tengen began hunting a demon in the Entertainment District, sending his wives undercover as prostitutes majorly backfired when Makio, Suma and Hinatsuru quickly disappeared. His plan to then send Tanjiro, Inosuke and Zenitsu undercover to find the missing women also went wrong when Zenitsu vanished as well. Despite how he'd treated the boys up to that point, he still blamed himself for Zenitsu's disappearance, admitting that his concern for his wives had clouded his judgment. Surprisingly, Tengen dismisses Tanjiro and Inosuke, no longer willing to sacrifice them for his mission and telling them that to survive is to win.
The Sound Hashira has been in a dark, volatile mood for most of the "Entertainment District" arc, but now it's clear that this is not who he is -- just who he has become as a result of his worry over his wives. When he finds a mortally wounded Hinatsuru, who apologizes for not doing more and asks to be left behind, Tengen is clearly riddled with guilt. Instead of belittling her as he often does others, he thanks her for a job well done and orders her to leave the city once she is healthy so that she will be safe from the coming conflict.
Once Tengen reunites with his remaining wives Makio and Suma, his mood dramatically improves -- he is once more the smiling, flashy Hashira he's supposed to be. A flashback reveals that Tengen has previously ordered his wives to always put their survival above all else -- including the mission, innocent people and even Tengen's own life. Declaring Suma, Makio and Hinatsuru the most important things in the world, Tengen orders his wives to ignore their training as kunoichi and always prioritize coming back to him safe and sound.
Further down the line in the manga, Tengen explains his personal history that has shaped him into a man who values the safety of his loved ones above everything else. When Tengen was young, he had eight other siblings, all of whom trained as shinobi alongside him. However, his father's intense (to put it mildly) training resulted in the deaths of three of the Uzui children, while the remainders were forced to fight to the death while blindfolded and unaware they were battling their own family. As a result, Tengen unknowingly killed two of his brothers, while the only other surviving Uzui son also killed his brothers. Unlike his last remaining brother, Tengen was horrified by what his father had forced him to do and fled his clan along with his three wives.
Tengen's instruction for his wives to prioritize their survival is a rejection of his father's training, which treated lives as worthless and easily disposed of. He never again wants to be responsible for the death of someone he loves, or even someone who is only following his orders. In spite of the horror of his childhood, Tengen has become a man who loves deeply, possibly more so than any of the other Hashira. However, only time will tell if his love for others will be enough to keep everyone alive for the rest of the "Entertainment District" arc.
