Standby Kiss: Ore no Senzoku Secret xx

Coming to save Aoi Yamato (the son of a huge enterprise and kidnapped for ransom) is Prince Charming... Or, more like an arrogant and rude bodyguard...! Lo and behold, this man in black is Ryou Uruha, the boy Aoi used to bully in junior high. He's supposed to be working for Aoi, but he has a cockiness and insensitivity about him that riles Aoi up. Yet, there's also a soft, gentle side to him amidst his brutal honesty, and Aoi finds himself gradually drawn in...

(Source: Renta!)