Figuring out the island

"You were human? What happened?" You need some answers.

"Well, the first day was tough. This place isn't bad, but I've never really been the outdoors type. I couldn't even manage to climb one of these trees to get at any of the fruit. In the afternoon, I met another girl. She had wings. On her arms like a bird, not her back like an angel."

"A harpy." Your helpfully provide, either because of your now perfect recall or because you're the kind of guy that's into monstergirls.

"That's what she said! Anyways, she got some fruit for me, real easy for her. It was one of the ones that look like pineapples, but they're pink on the inside. Really good, really tasty. But it made me weak and sleepy. That's when she...ah..." Pink bubbles begin to form inside the slime girl, bubbling up. Is she blushing?

"That's when she started pawing at me. She got me to take off my pants, and then, she, um...pleasured me with her mouth."

You press her on this, "Pleasure you how? Did she suck your penis?"

More pink bubbles now, "Yeah. Jeez!" She slapped her face with two wet hand to try and cover the blush, but it didn't really help at all, "It was my first time, and it felt really good...but, when I woke up, she was gone, and I was like this."

Interesting. "Before you woke up, did you pick a sphere?"

"You too? I picked the matter sphere. That first day, I was able to change the sand into glass lumps. It wasn't very useful as far as I knew, but it was super neat."

"The first day? Can you not do it any longer?"

"Not since I woke up as a slimegirl..."

Hmm. You've got a few theories in mind. One, sex with these monstergirls seems to turn a human into a monstergirl. That's not good. To be more precise though, it seems that letting a monstergirl make you orgasm triggers the change. Two, the powers you were given seem to only work if you're kept human. Your last theory is based on intuition. What motive would a harpy have to find and transform a human, then simply scamper off? Power. You don't have any proof yet, but you think that making someone else on this island have an orgasm gives a measurable increase in power. You aren't sure what power a monster girl gains, but you reason that it would enhance your Mind sphere if you were to do so.

You look at the slime girl. Would it be any benefit at all to make her orgasm? Or had her earlier defeat left her empty, with no prize. She did say her sphere ability was gone.