Simon's origins are unknown, but it is said that she was a cheerful girl prior to being experimented on. Mira is responsible for her current state. As a result of being experimented on, Simon's hearing skills have increased drastically that she can hear the faintest of sounds and can "hear" what people say by looking at their mouths. She was rather indifferent to being experimented on, initially shunning the rest of her allies away and preferring isolation.