I've already made a post partially talking about this yesterday, so this post is sort of a expanded version of this post. And I know some people are going to disagree with me both before and after reading all of this, but just hear me out.
I fully get that she had a horrible childhood, since she grew up on the Volcano island, (and it was really messed up what Darkstalker tried to do to her by turning her into a copy of Clearsight) but I don't feel like this justifies any of her actions at all. There are other dragons who grew up on the island, like Mightyclaws and Mindreader, who suffered through a lot of the things that she did, and still ended up being good dragons who didn't even come close to do what she did.
She's a delusional narcissist who believes that she deserves to be a Dragonet of Destiny, or the queen of the NightWings pretty much just of existing, who belittles Starflight for getting to be a DOD and live on the mainland (when he obviously had no choice over this, and spent most of that time at this point in a dark cave) and even straight up says in one of her letters to Saguaro that she wanted to brainwash Starflight into becoming a NightWing extremist if her plans to become the NightWing queen worked (which she even considers to be "kind"). And she doesn't even come close to apologizing to him for this, and goes as far as to ask him for some gifts in her letter to him shown in the Guide to a Dragon World.
She also kidnaps Sunny (who had done absolutely nothing to her, and even ended up saving her life later on, which she never even acknowledges) and tries to give her to Burn, who would've killed Sunny and stuffed her corpse in her weridling tower. And at the same time tried to give Burn the location of the DOD so that she could hunt them down and kill them, in exchange for an army of SandWings to help her overthrow Queen Glory, which I'm about to talk about more.
And finally, she tries to kill Queen Glory/overthrow her rule not once, but twice! And all because she was a RainWing, despite the fact that she had let the NightWings live in the rainforest despite a lot of them at the time being perfectly fine with genocide her entire tribe, and was genuinely trying her best to help her tribe and rule them. Fierceteeth in general shows that she has massive disdain for the RainWings, as she insults them whenever she can, and is heavily implied in her letter to Saguaro about how she wished things had gone for her that she would've attacked the RainWing's with the SandWing army she hoped Burn would give her, and might've even tried enslaving them.
Overall, while I do get a few of her points, and of course recognize that she had a horrible life, I just feel A LOT of her actions were inexcusable and genuinely vile, so I really don't feel that bad for her.
Also, I find it pretty ridiculous how she faces basically no consequences at all after Darkstalker's defeat, and that Glory just let her and Strongwings go free after they had just tried to assassinate her AGAIN! I get that she didn't want to put them back into Darkstalker's prison, since she hated it so much, but I think she should've just thrown her into a quicksand pit like she did to Mastermind, either permanently or until she got a new prison built that was more to her liking.
And the fact that she got to become the defacto leader of Renewal?! She's literally the worst possible leader to lead this group, as she represents some of the worst and most toxic aspects of modern NightWing society, and could end up dragging some of the NightWings living there back into their old ways. Also the fact that Glory had no objections to her leading Renewal, and actively traded with the dragon who tried to kill her/possibly enslave her entire tribe if she had the chance is just baffling to me.
Side note I already feel horrible for Fierceteeth's unborn children, as they're probably going to have a MISSERIBLE childhood with parents like Fierceteeth and Strongwings