Revenge of a tyrant

I'm not good with descriptions so here's the best I can do:
The story of revenge, death, a tyrant, and rebellion.
When prince Alex's brother, King Arthur died. She started to fall in a downward spiral. But then she started to focus on revenge.
How will she manage to hide the fact she is girl to a world who thinks of her as a man? How will hide the fact her brother is dead as she masquerade as him with out others finding out?

⚠️Trigger warning ⚠️
-self harm
-suicide
- depression
-Something similar to drug addiction, actually it's safe to say drug addictions