What Now, My Brother has Turned into a Loli in an RPG World (哥哥在游戏里变成萝莉了,怎么办) is a Chinese Web Novel written by Hundred Thousand Mercury (十万水星) and translated by Silva. It is ongoing with 16 Volumes.
While the otaku brother was fighting over the PC with his sister, they got drawn into the game world. Soon as they awoke, they found that the god made a mistake with the setting and turned the brother into a blue-haired lolita mage! …Without a choice, he (she) could only accept the outcome and train to become the strongest with his (her) sister in this RPG world!