It's so cool that you're still following her work! I feel like I've lost track of most of the people whose work first got me into fandom, which is a little sad, now that I think about it.

I love it (while simultaneously being extremely distressed).

That is one of my favorite fannish experiences!

Meanwhile, since my first comment I have realized that zarla wrote a fic where Gaster turns himself in to Asgore, and now I'm having fun looking at all the differences between that AU and yours. Like, Asgore and Alphys both have a hard time believing that Gaster would do this, but discovering the brothers on her own probably gives Alphys an advantage in realizing that Gaster really is a terrifying guy. And not only does Gaster not get a chance to brace himself before the agonizing confrontation in this version, it sort of... requires more of him, because Alphys really doesn't want to take charge of this conversation.

Poor awful Gaster. He might as well have let himself pick a favorite character for all the good his attempted detachment did him in the end!