Princess Azula

She is the dangerously unstable princess of the Fire Nation, daughter of Fire Lord Ozai and Queen Ursa, younger sister and arch-nemesis of Prince Zuko, and the archenemy of Team Avatar as a whole.Azula is an incredibly ruthless and manipulative princess who thrives to receive approval from her father, and outdo her brother. But underneath her ruthless demeanor, she's also insecure and unstable as she suffers from an emotional and manipulative abuse from her father (to which it influenced her deep envy towards her older brother for being favored more by their loving mother Ursa over her).