KNY x Aot x Grillby Reader x Undertale

Y/n was a fire monster from the underground. He was very good friends with everyone. He was polite and kind. Once monsters were allowed up on the surface he trained himself to protect his friends. He learns breathing style and so much more. One day he was sent to a different dimension where he meets the hashira. Y/n has become the Sun Hashira since he has been the only one to learn it. He has been slowly healing Ubuyashiki with his healing powers. But one day he and the others were teleported somewhere different.