Luxuru is a friendly low-class Apoptosis. She can join you after a battle.
Luxuru: "Ahahaa! Take me with you too. At this rate you're just paying for me to become worthless."
Promestein: "This is an unusual machine... The nerve center resembles that of an organic lifeform."
Luxuru: "What are you saying? I was originally human. I was fused to this machine, it's just my upper was never processed."
Promestein: "But most of your brain has been altered..... It can hardly even be called organic."
Luxuru: "...huuuh? Hey, that true?!"
Promestein: "Aren't you excited?!"
Jaide: "Luxuru type confirmed."
Luxuru: "Jaide type... Meeting in a place like this, fate is strange."
Jaide: "I am someone who does not know anything about themselves. Are you also searching for answers?"
Luxuru: "I do not care about that, I just want to drink the sperm of my prey."
Minelli: "You are... hiding in a chair?"
Luxuru: "No, I'm not exactly hiding."
Minelli: "If you are in a chair, how are you supposed to attract prey?"
Luxuru: "Do you even listen to people?"
She is required in the "World of Apoptosis" scene.