Otoko Gakuin Soushi: Shinobi no Otoko

Otoko Academy, a place where power is everything. Hazuki, (Age: 26, Student), the bodyguard to Shinobu, the young master of the famous Ogasawara group is a skilled but a little stupid "Nindiot." Everyday he does his best protecting Master Shinobu... But, he's not entirely out-of-it to ignore the fact he's liked by the sharp-witted disciplinary committee member, Kusumi! One day, his senior disciple, Kisaragi, insists he uses his body for espionage...! Just how is Hazuki's secretive love going to end up...?!

(Source: TORICO)