If Witch, Then Which?, Vol. 1 — Ato Sakurai

Ever since a lifesaving blood transfusion, Haruka Kuze has been indebted to Maruna Rinjou. The only problem: How do you show your gratitude to someone who barely gives you the time of day? So when he finds out she's actually a witch, Haruka swears he'll do whatever it takes to help her graduate from magic school -- even if it means cross-dressing as a girl! But does Maruna really hate him, or is there another reason she gets so flustered when he's around?