For Glitchtale Gaster...
Default says "You're the 1st of your kind. I'll make sure you're the last."
Neutral Frisk says "But now, after a life of endless pain... I have matured to something past a human... Yes... From a human, to a god."
X Gaster says "1 timeline, made with the best of others. And I know how to do it."
Void Gaster says "very interesting. Very, very interesting."