Board Thread:General Discussion/@comment-28431168-20160617130858/@comment-30438304-20161106194644

While it is a proper theory, but it lacks concrete proof for it to be considered as a fact. The only proof that is somewhat stronger is the time when Gaster was implemented into UNDERTALE, but other proof is very weak, and that's why it's a very unlikely theory. You need to assume too many things about a character that we know almost nothing about for it to be true.