You got it right. Before I go in to the Death Singer, I kill off the acolytes and knights and guns, so I won't get hit.
Remember, only go in to the Death Singer when she starts her song and everything starts flashing red. Otherwise, she moves around and blasts you to death.
English
-
I have done the fight many times the way you say, I made my comment because I don't think it's intended for knights to respawn after you kill them, and for the checkpoint to be given after such a delay after killing the boss.
-
This. So many unnecessary deaths. Easy burn as soon as she starts the liturgy.