Kamen no Maid Guy

Naeka Fujiwara appears to be an ordinary seventeen-year-old student, but she is actually one of only two heirs to an enormous fortune that becomes hers when she turns eighteen. With that date approaching, plots against Naeka and her brother Kousuke become a serious threat. Two servants are assigned to protect them: the capable maid Fubuki and a massive masked man who insists that he, too, is a maid, Kogarashi.

Kogarashi is absurdly strong, fiercely loyal, and treats everything from security to household chores like a military operation. Between assassination attempts, school life, and the humiliating disasters created by her own protector, Naeka often finds herself less worried about her enemies than about whatever Kogarashi will decide is the proper way to serve her next.