Ruby

"Let's play together again like in the old days, Nii?"

- Affiliation: Medusa.
- Birthday: January 24.
- Height: 157cm.
- Three Size: B88(F)/W57/H89.
- Likes: Waffles/Her brother, Souma.
- Dislikes: ???
- Will/Gem: "Red, Brilliant Crimson Fruit of Wrath" Red Berry Pigeon's Blood
Crystallizes blood plasma and produces rubies. It can even turn all the blood flowing inside a target into a blade, making it unrivaled in its ability to kill in terms of lethality.

She is a female leader of the enemy organization, Medusa.
She is also a childhood friend of the main protagonist Souma, whom she calls "Ani".
She is known as one of the greatest threats in the organization, and the number of lives she has sacrificed is immeasurable.
Her code name recognized by the Phrygian Military Army is "Kogyoku" which means "special strength".
Although she is friendly and has sweet affection towards to Souma for old childhood times, she is very antagonistic to Souma's classmates.