A possible concise summary is:
Seras, a vampire police girl, fights against Zorin, a Nazi vampire, who invades her base and kills her friends. Zorin tries to break Seras mentally by showing her traumatic memories, but Seras overcomes them with the help of her master Alucard. Seras then unleashes her full power and brutally kills Zorin, avenging her fallen comrades.
Here are the key facts extracted from the text:
1. A group of Nazis are fighting against a group of mercenaries.
2. Alucard is not present during the initial fight.
3. Seras is a vampire and Alucard's protégée.
4. Bernadotte is the leader of the mercenaries.
5. Willingham is a member of Bernadotte's team and gets severely injured.
6. Zorin is the leader of the Nazis and has a personal vendetta against Seras.
7. Seras has a troubled past and was raised in an orphanage.
8. Seras' mother was killed in a violent incident when Seras was a child.
9. Alucard arrives on the scene and helps Seras to regain her confidence.
10. Seras confronts Zorin and ultimately defeats her.
11. The fight takes place in a building, possibly a mansion or a castle.
12. The mercenaries are heavily outnumbered and outgunned by the Nazis.
13. Bernadotte gets killed by Zorin.
14. Seras is struggling with her identity and her role as a vampire.
15. Alucard has a paternal relationship with Seras and is trying to help her find her place in the world.