Амацука Меґумі

One day Megumi saves a strange man. In return, Megumi receives a magical book. After accidentally bleeding on the book, a genie named Pierrot appears and offers to grant him a wish. Megumi wishes to become a strong man's man. Pierrot, a trickster, inadvertently turns Megumi into a woman.

While Megumi is physically a very attractive girl, she still retains her masculine mannerisms and fighting abilities, which she uses very often, attracting the 'Megu-chan Protection Club', a group of misfit admirers. Nobody else knows she used to be a boy but was transformed into a girl; initially only Megumi's best friend, Miki, knew her secret, however the protection club quickly finds out.

A tomboy at heart, if she unintentionally displays any sort of affection for anyone, she is very quick to deny everything.

(Source: Wikipedia)