While walking up the stairway to the Surface, Frisk's group comes across a human that died at the end of the Great War just as the Barrier was being raised. The two Skeleton Monsters of the group can't help but feel unsettled at this grim physical evidence that dead humans really do look like them.
Also I know that according to the lore there was no human casualty in the Great War (or at least, not a single human soul was taken) but... no soul taken =/= absolutely nobody died in a friggin WAR imo
I believe a few humans did die but were simply left to rot in the scuffle instead of having time to mess with their soul and stuff.
This thing has been in the making for several years and I'm glad it's out. My plate is still pretty full but each thing I finally get made is still liberating.
Undertale (c) Toby Fox
Don’t worry. I can fix that: “alzaub Alzaud”