Pyre wrote:4.) Most importantly, Chi is pretty badass, she really went from a very derpy and clingy personality there to something very aggressive and self reliant.
She's just a big ol' kid. She wants what she wants and gets pissed when she doesn't get it- to hell with the reasons why.
I can't tell if her aggressiveness is born of being spoiled and hating to be kept waiting or her legitimate love for Mimi and the fear of what could be happening to her. I would 'like' for it to be the second option, but she is just a child after all, so it could easily be the first.
Well yes, that is very much the case and honestly she knows nothing about Mimi's condition so for all it matters in her mind Mimi might just be on a mission to pet all the puppies and kittens on Earth so no human child can, and as such there's no reason for her to really be concerned about what's happening to Mimi, but all the reason for her to just be mad she didn't get what she wanted.
However, what's really important is the behavior she is exhibiting when it comes to demanding what she wants... As a child, and how she's been acting as a whole prior to this, it would make sense if she threw a temper tantrum that was composed of screaming and yelling, but such an act of violence after being essentially threatened is very uncharacteristic of a typical spoiled child. More so, it's also the reason why she did it, it wasn't so much the lack of Mimi, even though that played a role in it, but rather because she felt the need to assert her dominance in her own realm.
Basically what I'm getting at is that she knows Him isn't someone to take lightly, and he has already threatened her, but even knowing this she's taking that risk in asserting herself and is willing to stand her ground in a very atypical manner when the spoiled brat personality is concerned. Even her expression in the last panel isn't that of someone throwing a tantrum, but rather one of "don't take me for granted, because I'm not just some brat."