1/2 Prince

is a Taiwanese manhua by Yu Wo and illustrated by Choi Hong Chong.

Plot
1/2 Prince is about Feng Lan, a wistful, yet cheery, 19-year-old girl who shares the same interest as her 19-year-old twin brother, Feng Yang Ming, to play virtual reality games. After being challenged by her brother, she is determined to become a male warrior in Second Life and prove her gaming skills to her brother without using "female benefits" in game. While trying to get the upper hand on leveling Feng Lan logs into Second Life too early and ends up being the first player ever to log on. As a reward for this, the Second Life superiors grant her wish to change her gender, an otherwise impossible request. Thus begins her adventures as an elf who is too stunning for the girl population to leave alone.

Other Sources

 * Wikipedia