'Monsters' and 'Humans', and the monsters are held to be magic. River can see the shadow of something terrible in her mind's eye and decides that first meetings are not the time to attempt to fish it up, any more than it would be time to fish up her own people's difficulties.

Besides, Great Papyrus seems like a fun guy. It'd be like kicking a puppy.

"We really do all come from different worlds," River murmurs, in faint awe. "Met someone not all that long ago who's a mechanical being, but not like the ones I'm used to. Nightshade, if you see them around, they're a deeply curious person, real interested in learning. There's even elves native to this world, still gotta meet the local ones." Here River helpfully flicks the tip of her own ear. "But hey, enough about that, here I've been just taking over the conversation. What'cha do for a living back at home, Great Papyrus?"