Ep 7. Transformation

Tanjiro, Inosuke, and Zenitsu are tasked with investigating a series of disappearances in the Entertainment District, an area notorious for its brothels and red-light establishments. As they begin their investigation, they come across a woman named Tengen Uzui, a Hashira (top-ranked demon slayer) who serves as the leader of the district's Demon Slayer Corps. Tengen agrees to help them in their investigation, but warns them of the dangers they will face in the district.

Meanwhile, inside a brothel, a demon attacks a group of women. The demon, known as Daki, has the ability to transform into anyone she has consumed, allowing her to blend in with her surroundings undetected. She is accompanied by her brother, a demon named Gyutaro, who has the ability to detach his arms and use them as weapons. Together, they are responsible for the recent disappearances in the district.

As Tanjiro and his companions continue their investigation, they discover that the brothel where Daki and Gyutaro are hiding is actually a front for a demon den. Tanjiro and Inosuke infiltrate the den, but are quickly overwhelmed by the number of demons inside. Just as they are about to be defeated, Zenitsu arrives and uses his Thunder Breathing technique to defeat the demons.

With the den cleared, Tanjiro and his companions confront Daki and Gyutaro. However, they quickly realize that defeating the demons will be no easy task, especially with their ability to transform and use their unique abilities. In the midst of battle, Tengen arrives, and with his help, they are able to gain the upper hand.

As Daki and Gyutaro are defeated, they reveal that they were only acting on the orders of their master, Muzan Kibutsuji, the primary antagonist of the series. They also warn Tanjiro and his companions that there are more demons in the district, and that they will need to be on their guard.

The episode ends with Tanjiro and his companions returning to Tengen's headquarters, where they are given a new mission: to continue their investigation and eliminate any remaining demons in the Entertainment District.