This guide will tell you what is the strategy to the Lisa fight.
Guide to Beat and Don’t Kill Lisa
All I did to not kill her while possessed is just sort of stand in the middle of the statues after the demon splits and just sort of rush to get the demon out.
You can tell which is which depending on if it vanishes or not. Of course if that doesn’t work and you get possessed just move the arrow keys away from Lisa until it wears off.
Rinse and repeat. Took me a few tries bc I didn’t want to accidentally kill her.