Second boss is a woman strapped up and being held prisoner alongside the main character. Starts off being completely bound to this segway thing, and then gradually starts to take her bindings off until she's fighting you in hand to hand combat. Even though she's a prisoner alongside the main character, she's been driven totally insane and can't be an ally.
Unfortunately the mask she's wearing never comes off, and she just dies at the end of the fight and is pretty much never mentioned again. Since all she does during the fight is let out a unsettling scream, you can assume that the mask serves as a pseudo gag?
https://www.youtube.com/watch?v=aa0-vNWNxCM
Lines from the game to give added context:
"She turned up one day. Destroyed everything in her wake and then BAM! She got caged."
"They couldn't make sense of her. She was so wild. So they put her in a cage."
"But you and me, we both know that being locked up fucks you up inside."
Reference sheet showing bondage design:
