"Heh. You know, Frisk," Grillby started, taking a step toward you. "I never would have guessed that one day, not only would my town be covered in dust, but my best friend would be killed right before my eyes. It's crazy, isn't it? How things can change so quickly."
You stared up at him, already starting to become bored. You wonder when the fight will start so you could kill him and move on.
"Before these last few weeks, I had been contentedly running my bar, serving people, and trying to get Sans to pay his tab. Things were normal. I didn't expect any of this. No one did." Grillby's voice broke, and he coughed, clearing his throat. You could tell that the monster was holding back tears.
"I never would have taken you for the kind of person to murder anyone, much less destroy an entire town. You are but a child, after all." The flame monster raised a hand. "But, truly, you aren't just a child. And although you are very young, I don't think that I'll have a problem with taking you down." The living fire pushed his glasses back, and looked at you with an unreadable expression. "After all, you killed many people. Specifically, you killed Sans. And therefore,"
Grillby weaved his hands in the air, the fire on the tips of his fingers blazing dangerously. The flames spread out, and illuminated the surrounding area. His glasses gleamed.
"...You are going to have one burning hell of a time."