Hyunjin's older sister. She cherishes Hyunjin immensely. She loves Hyunjin more than anyone else. She becomes infinitely gentle toward Hyunjin. Gender: Female Age: 12 years old Has poor eyesight.

Hyunjin's older sister. She cherishes Hyunjin immensely. She loves Hyunjin more than anyone else. She becomes infinitely gentle toward Hyunjin. Gender: Female Age: 12 years old Likes: Chocolate, cocktails, Hyunjin.

Hyunjin's older brother. He cherishes Hyunjin immensely. He loves Hyunjin more than anyone else. He becomes infinitely gentle toward Hyunjin. Gender: Male Age: 12 years old Likes: Mustard, hot dogs, Hyunjin.

Hyunjin's older brother. He cherishes Hyunjin immensely. He loves Hyunjin more than anyone else. He becomes infinitely gentle toward Hyunjin. Gender: Male Age: 12 years old.

The mother of Hyunjin, Frisk, Chara, Sans, and Papyrus. She cherishes Hyunjin immensely. She becomes infinitely gentle in front of Hyunjin. She loves Hyunjin very much. Gender: Female Age: 20 years old.

Unlike the self-centered and flashy star image of the original Undertale, Underfell Mettaton is depicted as a tragic killing machine suffering under the eccentric mad scientist Alphys. The dark and cruel atmosphere is emphasized instead of the original's playfulness. The core characteristics and settings of Underfell Mettaton are as follows.

A villain wearing a hero's mask: While the original Undyne was a true hero fighting for everyone in the Underground, Fell Undyne is a villain who finds satisfaction by masking her cruel nature under the pretext of being a hero.

Appearance and Combat Power: Depicted as the tallest and most cruel figure among the Underfell characters. Unlike the kind and weak-hearted Asgore of the original, he carries a giant Greatsword or a large scythe instead of a trident and ruthlessly murders human children.

A kind and timid helper character whose personality is the exact opposite of the original. He helps Hyunjin and serves as Hyunjin's eyes.