Into the Abyss: She Collected Monsters

Ruby's boyfriend and her best friend were both deceiving her, and when it came out she was left with nothing. Not long after, she fell into an endless run of instances, one deadly room after another with no reaching the end of them. She woke there as a Siren. Monsters that came for her could be turned around and made to follow her instead, and traps that killed other people let her through. She used the same pull on the four bosses who hold the instances, and one after another they took her side and stayed with her as lovers. The instances did not stay closed. What lived in them came out into the ordinary world and the arrangements people had lived under stopped holding, and Ruby went into that with the four of them behind her.