1. Umyonge (or, as I call her in my mind, Ramirez) is so badass that her Myon has to be terrified in order to balance out her badassness.
2. The UsuallyDead reason: her Myon is a reflection of her true state of mind. While doing these badass things, Ramirez is actually terrified out of her mind. This somehow makes her five times as badass and adorable than reason 1.