Nova (They/Them) isn't the main focus of my story but they do play an important role which is why I'm so focused on this. I feel like I'm straying a little too much into the cliche side of a villain that is kind of moving their entire purpose from the original plot. One thing is they're not a villain, they’re an antihero and their job is to teach the protagonist the concepts of broken relationships, betrayals, and heal With self-care.
For context of Nova backstory, short version they were once a hero who saved their planet from demon-like creatures, became a high priestess in a coven they made with their closest friend Lavender (Any Pronouns), Lavender sets Nova up for an arranged marriage with Lavender’s sister for power purposes and to make lavender sister happy, Nova's in a Loveless engagement and decides to take a vacation, finds an amazing group of people and two people they truly fell in love with, goes to Lavender saying we should open our borders to nearby planets and wants to call off the engagement, lavender gets extremely angry and banishes Nova from the coven along with stripping their position as high priestess and giving it to their sister, Nova gets revenge by starting a war destroying not only the coven but the planet itself.
I don't know why but this feels like it's straying into a cliche villain Having a temper tantrum. I want to show that they were extremely hurt with what happened, not only being cast out for being in a Loveless engagement and having their position taken away from a cub and they've created oh, but it was all from the person they trusted the most, their best friend, their sister. Is there something I should add or remove in their backstory to make it less cliche or is there no problem with it?
(also this is so long I’m so sorry)
Personally I don't see this as leaning into a cliche villain archetype, especially since Nova is an anti-hero that's being helpful to the main character and isn't the antagonist of the story. I think the one thing that you should focus on is Nova's feelings and how they exactly they snapped and destroying everything…their actions are technically justified in a messed up way but thats the beauty of anti-heroes right? So as long as you make sure that the reader can feel for Nova and their pain then in a way it doesn't seen like she's having a temper tantrum but rather more of an emotional breakdown.
To actually show how hurt she was, having personality or moral changes as Nova falls apart with Lavender and being forced to do things that they don't want to do. Maybe Nova is a very adventurous person that can't be tied down and those restrictions being mixed with stress, pressure of being a high priestess and built up anger to finally snap.
Because they're helping the protagonist too, make sure that they've developed a bit from the war against Lavender? Are they proud of what they did or wished they did something more calm? Do they still think what they did was justified? Exploring that area of questioning also makes sure that the reader can at least partially understand whats going through their head at the time. Maybe they were much more impulsive back then and having that mixed with great power just resulted in those actions and nowadays Nova is much more controlled but still thinks what they did was right?
Overall just kinda dig deep into her mental, physical and emotional well being during her backstory and play with the anti-hero idea! Morally grey characters are challenging but fun, you just need to find that sweet spot of justifications of actions but based on what the backstory is you could 110% do just that. If you need more help or advice just ask!