Read manga: Bodyguard (SABATAMA Yumi)

manga
Summary:

Rumor goes Hachimono would kill you if you do anything to his friend Minami. But no one knows the two-faced personality of Minami that often victimizes Hachimono. Then one day Hachimono receives a challenge letter, will Minami take action? And is it really a fight that awaits Hachimono?