She does a lot of damage, but it's possible for her to be killed, therefore it's suggested that you help her by attacking Henryk to ease some of the pressure. Be careful not to hurt Eileen since your attacks can damage her as well. She can turn hostile if you damage her too much.
Can you fight Henryk after killing Eileen?
The encounter with Henryk is triggered regardless of speaking with Eileen outside Oedon Chapel, but is recommended to speak with her in order to obtain the "Shh!" gesture. ... If Eileen is killed by the player beforehand, Henryk cannot be fought.
How do you keep Eileen alive?
- Sneak behind him.
- Apply Fire paper.
- Backstab and visceral.
- Don't get killed, play it safe, wait for Eileen to arrive.
- Get Henryk between you and Eileen. ...
- Basically gank him as much as possible while keeping yourself safe, drawing attention away from Eileen often, and doing big hits so he dies quickly.
