Yuu was once a princess before she was a ninja. She had loved a ninja named Shui and they'd spend many a night together beneath the lemon tree in her garden, until one night Shui received the order to k.ill her, and he did as he mercilessly ripped her heart out as proof of her death. Zheng [A renowned and powerful ninja dragon] brought her back from the dead as a kitsune and she swore undying loyalty.