"I know that it's hard to believe that a kid, Meng Jie, possesses the power of Creation- Yang, but this is the truth and you all have to believe it.
Meng Jie has used her Yang during the attack of Wicked Soul Society to bring back both arms of Elder Hu Ling as it got blow away when he blocked the enemy attack to protect Meng Jie.
She is unable to use the power again for some time" Chang Niu told everyone
Everyone wanted to see what the power of Yang really looks but after hearing that Meng Jie has already used her power and right now she can't use it again, they are happy and also worried.
Happy because Meng Jie can't use the power of Yang always, this means that she can't exploit her power if she decides to walk on the wrong path.