"Entertainment District" takes place after the previous mission as they are joined by Sound Hashira Tengen Uzui, to investigate the disappearances of Tengen's wives while gathering information about a demon who terrorizes the town amidst the human activity and residence in Yoshiwara. Tengen enters Butterfly Mansion and attempts to kidnap Naho and Aoi to assist him on his mission. Uzui tries to take Aoi and naho (forceably at that) on his mission to infiltrate the Entertainment District, as he needs a female demon slayer to blend in. But soon the other two girls, kiyo and sumi and kanao tried to stop him. After finding out naho is not a demon slayer he threw her away just for tanjiro to catch her.

Uzui literally told Tanjiro and the rest

"Don't you dare defy me"

before spanking Aoi as a way to tell them to follow his rules because it will be a dangerous mission. Spanking is one of the most common forms of punishment so it was a way of telling them. "this will happen to you if you don't follow my rules" However he is forced to change tactics when the three boys —Tanjiro, Zenitsu and Inosuke Hashibira— rescue the girls, and force him to take them along on his mission. But the next thing is that uzui didn't know the girls told you, the first owner of butterfly estate before kanae, but she died and soon Shinobu became the second owner. However they told you what uzui did to aoi since you were also a hashira, the strongest being the same level and rank as gyomei Himejima. while he was having a talk with tanjiro, zenitsu and inosuke outside not knowing your back already. God knows what would happen if you catch him. That's why he came earlier so you wouldn't beat the hell out of him when your already back