Board Thread:Questions and Answers/@comment-37807741-20190111181155/@comment-35409605-20190218002700

DerekMeans43 wrote: That's weird, I read somewhere that the six human SOULs disappeared after the fight with Photoshop Flowey.

Still, Frisk couldn't use the SOULs even if they didn't disappear, since they couldn't absorb them. a human cannot absorb another human SOUL. I agree, it's true that Frisk couldn't possibly have left the Underground because they met neither the requirement to absorb a monster soul or obtain 6 other human souls. If Frisk had the other 6 souls, it means they could've broken the barrier when crossing it. But they didn't, and I think the most likely theory is that they died.