Mayu Nuru has spent most of her life exploring the Pink and the Red. She is, perhaps, a tentacle connoisseur. She's too acidic to enjoy the attentions of parasites, too squishy to be contained, and too resilient to be seduced. And unlike most slimegirls, she seems to be able to think about things that aren't sex. Most of the time.
There's no real need for her to be too cautious; there's always someone along to extricate her eventually, and she has the endurance to manage for weeks even if nobody happens along. Things just seem to work out for her! She was trapped once by that particularly nasty pit but a tentacle queen just happened to be passing at the time and things were sorted out easily.
And that's how she comes to be at the Deep-Heart-Glisten-Palace; because she knows that something interesting is going to happen, and she wants to be there! Maybe someone will listen to her about the stars? Maybe there'll be nice new people to fuck? Who knows!
She just knows that something amazing's going to happen to her. After all, it usually does!