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.
Tengen Uzui is the new Hashira for Demon Slayer: Kimetsu no Yaiba's "Entertainment District" arc, and he certainly stands out. Despite coming from a Shinobi family, he's flashy in both appearance and personality. Shinobi, more commonly known as ninjas, pride themselves on tradition and discipline, dedicating themselves to their martial arts and other techniques. But Tengen stands apart from his family, having already broken two major traditions.
One of the perks of being from a Shinobi background in Demon Slayer is that when Tengen came of age, the family's leader chose three suitable wives for him, as is tradition. But here's where Tengen breaks from the mold -- the leader chose only two of his wives, Hinatsuru and Makio. Suma, his third wife, wasn't selected by the Shinobi leader.
Suma approached Tengen of her own volition, despite it breaking a major Shinobi tradition. She desperately wanted to be one of Tengen's wives and did everything in her power to make it happen. This goes against Shinobi norms, but Tengen doesn't seem to mind. In fact, he treats and loves Suma on equal terms as his two chosen wives. However, the family leader would have seen this as a blatant sign of disrespect, going against his direct authority. It may have even put him and Tengen at odds, making the latter's transition to a Demon Slayer that much easier.
The second Shinobi tradition Tengen breaks away from is putting his life, as a warrior and as a husband, second to that of his wives. During Season 2, Episode 12 "Things Are Gonna Get Real Flashy!!", a flashback sequence shows Tengen talking to his three wives before they started their mission in the Entertainment District. He instructs them to put their own lives first -- they are the priority. Even if it means sacrificing the integrity of the mission, Tengen wants them to come home safe and sound.
This breaks from classic Shinobi tradition in multiple ways. First, the Shinobi always put their lives on the line for their mission, so Tengen instructing his wives -- who are Kunoichi (female Shinobi) themselves -- to do otherwise is a major break from the norm.
Secondly, Tengen, as both a husband and a Shinobi, would typically be the most important figure in their family. So telling his wives that their lives are a higher priority than his own is definitely not traditional. Since the male was known to be the breadwinner in the family, everything depended on their success, which inevitably meant that their lives were more important because they supported everyone else. Even though that mode of thought is outdated, the Shinobi tradition kept it alive, especially since they had three wives to take care of. This is why it's surprising that Tengen puts their lives ahead of his own.
Tengen Uzui is a flashy character in more ways than one, but it's his deviation from the traditional Shinobi practices that particularly makes him stand out -- even by Demon Slayer standards.
