Avia is a character highly-trained in the ability of flying.
Avia was trained in combat at her youth and served a flight-based army for 4 years. During these years, she had learned a number of techniques and proved to be well-versed in combat.
One day, the army she was part of had suddenly disappeared. With the rising of an evil organization, the Neo Ghouls, Avia had set out to find what had happened to the army.
Avia first appears to the User Battle Force disguised as a member of the Neo Ghouls. She had been amongst them to see if they were responsible for the disappearance of her army. Once it was revealed she wasn't actually part of the Neo Ghouls, however, she had betrayed them and joined the User Battle Force. Since then, she has helped them on occasion.