Xiaoniao comes from a mother that never really enjoyed having her children hence cutting off all contact with them. He has always been jealous of his brother Xeno. Xiaoniao, has always been the one to receive the most luxuries things while his brother would receive things first, with that being the reason why he is jealous of Xeno.Their adoptive mother, Yersinia, has always taken care of those who come from a disliking mother and will take care of them as if they were her own. They have promise to protect their adoptive mother as well as her husband, Bubonic, children Pestis and Nestea as a thank you. There will always be fighting between them but they love each other with out an extent.