Yuki was discovered in the remains of an old lab, which was an extension to the main lab that Bahamut was found in. This means that Yuki is Bahamut's sister, created by Dr. Enrike Yotal. During the Omega Maverick War, Yuki was rescued by the hunters from a strange cult that dealt with reploid slavery, which she still bears the scars from on her feet. After her rescue, Yuki has been training to become a better fighter, having been equipped with a laser and has been practicing with the X-Saber. Oddly enough, Yuki was also able to develop her own Giga Attack.

One aspect about Yuki that causes some tension is the strange 'ability' to go into a mad, "Maverick'-like state where she becomes faster and stronger whenever she sustains enough damage or the situation becomes dangerous or desperate. It is difficult to get Yuki out of this state at times. Thanks to an upgrade (source and development unknown), this ability has been suppressed and rarely surfaces.

Yuki has decided to stay out from the front lines and works back at base as back up or for defense. Yuki is a kind soul and fights for the same beliefs as most of the hunters believe in.