The Main Protagonist of Undertale. Their attacks are their Actions.

Chara, the Main Antagonist of Undertale, is the one who is "The First Human".

The Master of Puzzles.

Though Sans may be lazy, he's got Bones and Gaster Blasters on his side.

King of the Underground.

The Final Boss of the True Pacifist Route. He may seem like a normal goat but is powerful.

Asgore finally could get to see her again in the True Pacifist Route.