Hey I have a question so if Bowsette is Bowser’s sister, then does this mean that Koopa King is also Bowser’s & Bowsette’s dad or grand dad? Or a relative to the Koopa family?

If you’re talking about King Koopa from the animated show, then nah! I actually never considered headcanoning King Koopa since he was basically a different incarnation of Bowser, but I suppose he could possibly be used for like, their grandfather or somethin’. As far as Bowser and Bowsette’s parents goes, I actually did some art of them ages ago:

Brutus Koopa and Ursa Koopa; might give ‘em a redesign since its about a year old, but yeh. owo