Kabuto Fujiko from the eroge Sei Brunehilde Gakuen Shoujo Kishidan to Junpaku no Panty ~Kacchuu Ojou-sama no Zecchou Omorashi~

No matter how you look at her, she looks like an exhibitionist. A bucket-head with tits. She is a graduate of the school and the legendary strongest knight. Although she graduated, she still walks around the campus as if she owns the place.

She is daring, thinks outside of the box, and goes her own way. She is a genius who has mastered the art of swordsmanship just by watching her father and the protagonist train back at home.

In fact, she is the older sister of the protagonist and always keeps an eye on him (it's more akin to stalking).