ホルン・スティープル

Magic type: Darkness attribute

A strong-willed girl who likes to tease the main character, but is actually a good friend to him.
Although she is feared because she belongs to the horned tribes (a certain tribe supposedly eats humans), 
she nevertheless takes pride in bearing a horn.

Suddenly disappears throughout the second half of the game when it's not her route.

 
It is revealed in her route that she came to the school in search of a certain someone, and that the absence at a certain point of the story is due to her running out of time when continuing to attend school.

Dating back to her early childhood when she left her village playing in the forest, she meets a certain boy. 
She got hurt while playing with him, so he carries her back and is rewarded with a kiss.

Unbeknownst to her at that time, she accidentally shared her magic through that action, and will inevitably die within a few months after the start of the story if she does not find the boy and retrieves her magic from him.

/