A companion of Nyx who looked for them after their disappearance, climbed Mount Ebott, and was seemingly never seen again. The Human spent some time with Toriel, but quickly left after seeing no signs of Nyx, and practiced their magic upon learning about Soul Elements from a book written by a human dropped off at the Snowdin library. "Jonah" was not the legal name of the child but something they picked, and it probably won't ever be as Jonah met their fate at the hands of Sans, as the child fell before he made his promise with Toriel, and Sans handed Asgore their Soul. Within the soul jars, Jonah could now see their friend Nyx, also in a jar, but they are now trapped too.

Jonah would be far from the last human to go through this.
(Also, this be an AU where humans can use magic, but have to learn it to become powerful unlike Monsters. Undyne is an example of a Monster that uses Determination, something generally otherwise seen in humans naturally speaking).

Other UT-related Skins:
Chara Interpretation
Yellow Soul Interpretation
Cyan Soul Interpretation
Unused Sprite Slim
Unused Sprite Classic
Frisk Skin