A transgender woman who enjoys sexually dominating people who identify as being Queen of Swords (or Queens of the Sword if you want to make it sound fancy) using her massive girldick. Despite being called a king this is not denoting someone of the male gender, simply someone who takes a cucking role in this dynamic.
See also:
Jack of Swords
Hotwife: I finally found a King of Swords to destroy my pussy with her thick, soft girl cock! Isn't that great honey?
Cuck: Mhmmm, can I please watch? I promise I'll donate to the Trevor Project after I'm done like a good little ally.