Um well, it was kinda foreshadowed? She was a character in the OVA Out of Control. Although, she served no real purpose and was just the Guyver 2 unit. I'm not sure why they decided to go with her over Lisker, but bringing her into the manga was kind of a nod I suppose. Overall, she's very lackluster and just slightly serves to balance out the insane Zoalord team, but if you're interested in her backstory, I'm guessing it's the same as in the OVA?
Quick warning about the OVA, in case someone googles it because of this post or something, it's hard to find because the unit binding with Valkyria does kind of a tentacle rape thing.