[Hey, if he's gotta problem with royalty in Hadriel, he can take it up with the Door. Sans ain't real sure as to what other royalty here is lingering about, but now he can be certain of the fact that there's more than one of them. Great.]

Can't get any green magic to work for me, myself. I ain't what you'd call the strongest monster out there, magic-wise.

[It's possible for some monsters to learn it, certainly. But it varies, in essence.]