The Faulty Fantome Prototype
FantomeShe was a rejected prototype created by Professor Katie who wasn't satisfied with her design back then.
Katie wasn't sure what to do with her so she abandoned her and unintentionally forgot about her.
Upon her activation, the Faulty Prototype wishes to get revenge against Katie for forgetting her and the finished Fantomé with the intention of becoming superior to both of them.
Generally, she's inspired by Virus Charu from サルゲッチュ! ミリオンモンキーズ