He is the ruler of the Underground and its denizens, monsters. He is the ex-husband of Toriel, father of Asriel Dreemurr, adoptive father of the first human, and the penultimate boss of the Neutral Route. While not evil or malicious, he serves as one of the main antagonists, planning to kill seven humans and use their SOULs to break the barrierwhich traps the monsters in the Underground.