Stella

Stella is a little blonde girl from an orphanage in England that Sister ran. Whilst initially thought to be small and cute, she is a powerful fighter and sometimes speaks in a threatening tone to show her superiority. When she is angry she has the ability to turn into a giant and look extremely musculine. She has crush on Sister and also is his disciple.

She also might be parody of Biscuit Krueger from Hunter x Hunter series.