It looks like you're looking for of the hentai anime series Kuroinu: Kedakaki Seijo wa Hakudaku ni Somaru (often shortened to Kuroinu or Kuroinu: Chivalry of the Failed Knight — though that last one is a different series, so careful).
There is also a separate series titled Kuroinu II The Animation , which began releasing in 2021. If you're having trouble finding it, let me know: kuroinu kedakaki seijo wa hakudaku ni somaru where is ep 3
"Kuroinu Kedakaki Seijo wa Hakudaku ni Somaru: Episode 3 Update - Where to Watch and What to Expect" Episode 3 It looks like you're looking for
The original adaptation, produced by the studio Pink Pineapple, consists of only two episodes. The series was structured as a two-part OVA (Original Video Animation), covering the assault on the "Fortress City" and concluding with the surrender of the Dark Elf Queen, Olga. The series was structured as a two-part OVA