Brazlen

Given a family tree of the last six generations, the cultured Lady Brazlen can point exactly to where her lineage intersects with the Royal Line, not so long ago. The connection is a tenuous one, a daughter of a cousin of a spouses step-uncle sort of thing, but it is enough, she feels. Brazlen will be queen if she has to knock the old kings lazy, pompous butt off His throne herself. Luckily she can simply pay someone else to do it while she gathers allies outside His court hall.

What do you do, when you need a king removed and assassins are just so out of fashion? Bankroll a rebellion, of course. Find some peasents whose needs aren't being met, make a few shiny promises and give them nicer pitch forks. Set them lose in the kingdom to recruit more peasents whose needs aren't being met. Give them nicer pitchforks too. Eventually, they'll make an army to breach the castle, the King disappears in the inevitable battles, and with the support of her Noble allies, Brazlen will be conveniently available to fill the vacancy.

Or course, sometimes the peasants find an allegedly disinherited child princess instead of other angry peasents, and rally around her as future queen instead of their gracious benefactor, but it's fine. Brazlen will work around this, and should the coming uprising shatter on impact, young Stella will either make a convenient scapegoat to be executed in her place, or disappear in the fighting with her supposed father. Either way, Brazlen will be the next queen.