It just occurred to me that the canon fantrolls are actually Universe C trolls, since the cherub in Aranea's story destroyed their planet and eventually laid the cherub egg on old uninhabited Earth. also maybe if not on earth c, a session could start on another planet? If the frog is healthy, it would eventually reproduce right? I imagine even without external forces, a universe can still die. so it'd have to produce offspring.

Yep, the Canon Fantrolls are in Universe C. And it’s likely the Frog can produce another Session somewhere at some point, yeah! Whether it can die or not, though, that’s relative- It IS a living being, but it’s also a Universe, so rather than lifespan, I’d say the most immediate threat to the Universe C is The Breach, unless John can zap the entire Universe into the Blank.