Board Thread:General Discussion/@comment-26006155-20190617222636/@comment-26006155-20190726171220

It does seem like the Followers are from another reality, where Gaster's memory wasn't erased.

And if Gaster's Darkest Experiment was, in part, the creation of the Dark World, that probably is a continuation of the Alpha Timeline, that's still out there, no matter how much Sans messes with the Beta Timeline of Undertale.