Undertale belongs to Toby Fox.
Underfell belongs to the au community??(i think)

Beast: Underfell Sans

Bell: Classic Sans

Inventors("Bell's" brothers, two twins): Undertale Paps and Underfell Pap

Bookstore owners: muffet and grillby

Bar owner: chillby

Gaston: ut flowey

Gaston's minion: ut Chara

Castle inhabitants

Candlestick: Undyne (ut)

Clock: Alphys (uf)

featherduster: Alphys (ut)

Teapot: Toriel (ut)

Teacup: Frisk (ut)

Wardrobe: ut Mettaton

Footstool: annoying dog aka toby

Rose: red rose uf flowey