Nisemonogatari EP11 - Tsukihi Phoenix, Part Four

After learning from Shinobu that Tsukihi is actually a supernatural being that endlessly reincarnates as a human child after dying, Koyomi leaves Karen standing guard at their house's destroyed front door before setting to the place Oshino used to live to confront Yozuru and Yotsugi. To prepare for their clash, Shinobu draws some of Koyomi's blood to recover part of her former strength and upon meeting the two, agrees to fight Yotsugi while her master deals with Yozuru. Yozuru reveals to Koyomi that she, Oshino and Kaiki were friends from college and it was Kaiki who told her about Tsukihi being a phoenix. After viciously hitting Koyomi, Yozuru learns that her partner was easily defeated by Shinobu, and just when she is about to confront the vampire, Koyomi rises again, claiming that he would never give up on his sister, no matter what kind of creature she is. Realizing his determination to protect Tsukihi and that he never fought with the intention to kill her, Yozuru decides to give up and leaves peacefully with her familiar. Koyomi returns home to check on Tsukihi and declares to her that he will soon introduce his girlfriend to his sisters. In the end, Koyomi is seen meeting Hitagi at a beach.