Sakurazaki, Setsuna

桜咲刹那

Setsuna is a Shinmeiryu swordswoman from Kyoto who was taken in by Eishun Konoe, Konoka's father and the leader of the Kyoto Mage Association. She is childhood friends with Konoka and her protector.
At the start of the series, Setsuna is relatively cold toward Konoka, wishing to protect her from the shadows because she cannot forgive herself for failing to save Konoka when she nearly drowned in their childhood. She does eventually open up to Konoka after the Kyoto arc and begins calling her "Oujo-sama" and "Kono-chan."
Setsuna's pactio, Sica Shishikushiro, is a wakizashi which she can summon and multiply at will to strike targets like missiles. Due to her training, she is also skilled in anti-demon arts and is the one who taught Negi how to create shikigami from paper.
Setsuna is a hanyou like Koutaro, specifically a crow. She was expelled from her people because white wings are considered a bad omen, and Evangeline implied that she is an albino using hair dye and contact lenses to appear human.
A running gag in the series is that Setsuna and Konoka appear to have romantic feelings for one another, yet Setsuna denies it whenever they are stumbled upon in romantic situations or asked about her preference.