How Azula developed a manipulative side
Because since a young age, Azula learned to be an accommodating child. She tries to fit herself into the wishes of Ursa and Ozai, who are parents with opposite nurturing styles and ideologies, neither of them was a good moral influence.
Ursa and Ozai are different and difficult who did not connect emotionally with her, only demand what they want her to be. And this eventually made Azula study people's rules and deal with them as such.
Just look at this. I'll use Zuko as an example:
"We are brother and sister. It's important for us to spend time together! Don't you think so, Mom?" [Shoots her mother an innocent smile.]
(This is something Ursa wants and Azula knows this would get her her mother's approval. After all Ursa's priorities were Zuko and manners (never morals))
_
"Azula told me everything. She said she was amazed and impressed at your power and ferocity at the moment of truth."
(These are qualities Ozai loves and focus on.)
Both of these examples are strong acts of accommodating.
But there are no fake either, though, which is why I used the word accommodation instead of manipulation. Azula really does enjoy playing with her brother as siblings and she was really happy and proud of Zuko when he chooses her & their father's side, when they fought together as a team in BSS.
This was Azula trying to please demanding, emotionally unavailable parents whom she can't really understand.
This accommodating nature paved the way to her manipulation tendency of people later by her examining less difficult-to-understand (and less threatening) people's rules and play them.
She even play the perfect princess role yet she has no social skills. Azula's always been playing roles. She's rarely honest even with herself because of this accommodating, emotionally repressed nature.





















