so im just gonna say it now and explain: deltarune is an au of undertale where the humans lost the war rather than the monsters and were sealed underground in exchange for the monsters losing their magic. kris is an outlier who somehow escaped being sealed underground.
so in the anniversary stream, gerson tells us that when the monsters were sealed underground, humans sacrificed all their magic creating the barrier.
in deltarune, we haven't seen a single monster use magic. you'd think we'd have seen toriel or asgore using fire magic but no we haven't. also most monsters that enter the dark world act like being magic and stuff is the coolest thing ever when they SHOULD be able to be magic in the light world too. unless im missing an example i don't think we've seen a single lightner use magic
monsters in hometown act like kris is a unicorn or something. they ask questions like "what's it like having blood" and seem to have literally no knowledge about humans. if humans and monsters both lived above ground, like if it's a monster-dominated town they might not know a lot about humans but you'd think they know more especially cuz they have the internet.
now granted we haven't seen kris use magic either but it could be that because they were raised by monsters they don't know how and i mean. they have done weird stuff. they can constantly rip their chest open with a likely dirty knife and be totally fine
i find it hard to believe every single one of a species could be sealed underground. in undertale a few monsters definitely got away, i think it's just the majority of them that got rounded up.
anyway yeah. i think i've made my point clear
bonus theory: all humans are genderless. im not gonna deny that kris is like agender 31 citations n shit but, this might be controversial but i think they're the human equivalent of cis. u can interpret them however u want but im talking about like lore right. frisk is genderless. chara is genderless. kris is genderless. the human that gerson was in love with is genderless. i think 4 is a pattern.
so my main takeaway here is agender wizards living in a mountain thank you have a nice night