She's not a joke, she's just a fun NPC. (Though, Sane Abdul is cooler. I'm basically a hair trigger away, at any given point, from running an Arabian-themed campaign.)
I will be honest, there is a GMPC in my campaign.
His story begins with a village threatened by a great panther (that they created to kill an army for them, but, you know, stayed hungry afterwards, since it's in his nature to be terrible and hungry and clever.)
He tricked it into a spike pit, but even that only weakened it enough for him to chain him down, and in the struggle he lost his liver, his heart, his lungs, all of his organs! The villagers, thankful for his sacrifice, gave him a great, honorable funeral.
Which he showed up to and asked "Who's that in the coffin?"
And, to this day, he remains - a tough old man, all his clothing stained eternally red from his incurable wounds, who sees "being a hero" as the only goal in life, and "being a hero" translates directly into "killing large dangerous things".
He competes directly with the heroes from time to time, and occasionally his brutal quests line up with theirs - when demons attacked a town during a festival, and a huge, terrifying one appeared, he said "I'm gonna count to ten, and if it's still alive by then, I'm killin' it."
Oh, yes, and he double-crossed both the heroes and a mad priest of the Moon in order to allow himself to A. Technically Fulfill a Quest and B. Get close enough to the moon to carve "Crimson was here" into it.
He carries a huge jug of liquor mixed with healing potion at all times, which he chugs from constantly. He's prone to going on long tirades about how heroes ain't like they used to be.
He is the only person in the entire universe who cusses.
(He's basically the fallen Great White Hunter - ancient depictions of him show him as being dressed in all white. Now it's stained, of course...)