Asgore

Asgore is one of the main characters in Underfell.

Design
Asgore is a goat-like monster with two long horns, yellow eyes, goat-like nose holes and mouth and black beard. He wears a red and black cape. Underneath the cape he wears a set of golden armor. He uses some sort of a long red weapon (likely a trident, similar to Undertale Asgore's Trident).

(possibly outdated) Personality & History
Asgore used to not be completely deranged with hatred. Toriel did hide Chara from him despite this.

At some point, Asgore would come across Chara before they set out the plan to convince him about humans. At first, Asgore seemed somewhat welcoming to Chara, which threw both Asriel and Toriel off. Soon afterwards, Asgore poisoned Chara. Then, Chara fell ill and spoke about wanting to see the golden flowers in their village. Asriel then brings Chara there, but then the humans thought that he killed Chara. So the humans battered Asriel and he turned into dust the moment he returned to the underground.

Toriel finds out that Asgore was responsible for poisoning Chara, she immediately detaches and goes into hiding, Asgore blames Chara for meddling and ruining his family. He then becomes the most hateful monster in the underground.