Those Practitioners that work with Goblins. Technically a female Goblin King is called a Goblin Queen but forget that. There are also different permutations where they dip into specific branches of practices, such as Goblin Raider or Warrens Runner.
The focus of a Goblin King's magic is to offend people others and get in the enemy's way. It deals with conflict and gaining tools. These include a wide variety of goblin items and weapons that the practitioner can use in addition to being able to force Goblins into a tool or weapon form for the practitioner to use.
They are known badasses that carry carrying tools and weapons on them.
When working with groups of goblins some kings will to try to accessorize and organize them to make a pattern.
Firstly, king is derived from a Norse word that means "ruler of Man" Man in the sense of people over just those with dicks. As such the term was originally gender neutral and thus fits with this article.
Secondly, the background of sexism in the tradition bound world of Pact makes the choice of title apt.
Thirdly, suck it it's about Goblins.
↑Goblins Goblin magic is, well, offensive, and not simply in the ‘aggressive’ sense of the word. The most powerful goblin magic aims simply to hamper the enemy more than it does the practitioner. Earning the respect of goblin enables them to be claimed as followers or as prizes, with conquered goblins becoming tools or (more frequently) weapons the practitioner can collect and use. - Pact Dice: The Practices - Wbow Version
↑“Mags Holt, itinerant goblin queen,” the practitioner said. “Are you a goblin king?” [...] “Wasn’t sure you were the type to be a goblin king,” Mags said. “You never know for sure because you get some weird ones, sometimes. But you look out of place.” - Excerpt from Out on a Limb 3.7
↑“So you’re in charge?” Zed asked. He shifted from leaning against the hood to standing. He smiled. “You keep implying threats, but I don’t get the sense you’re that bloodthirsty. You have goblins but you’re not goblin queens. You’re not carrying an assortment of nasty tricks.”
“We’ve got a couple.”
“But you’re not loaded to bear like one of them would be. You’re not on the same page as them. I’m so darn curious.” He smiled, excited. - Excerpt from Out on a Limb 3.6
↑Avery spoke up, “Verona thinks the way Bristow set this up, the Aware are all interlinked.”
“Goblin warlords will do this. Goblins tend to come random,” Toadswallow said, getting to his feet with a grunt. “But if you pick out a good assortment that looks like they belong together, all with similar faces or matching names or… I don’t know, a farter-light, a spitter, a belcher and a big guy to match the four elements. It starts to look like this crapsack world of ours is starting to bend to your will. Goblins are random but you’ve got a nice matching collection? Must be meant to be, so you better get on board, little nuggets. Then the more they believe it…”
↑Liberty cackled, and she cackled all the way into the arena. She had what might have been a deck of cards or a collection of drawings, and she held it as a stack, doing the ‘make it rain’ gesture to scatter them. Where they landed, goblins about Gashwad’s size appeared in the short grass. [...] Liberty snatched a Gashwad-sized goblin off the ground, whispered something to it, and then hurled it.
It started to smoke, then ignited.
It detonated into a ball of fire a second later, it left the field burning. Avery had to change direction and hop over goblins.
↑“Beat some people up? I’m a raider princess, I kick the door in and I need people to cover the flanks. You gotta be ready to deploy through the nearest Warren hole. My power greases the way, I whistle and you’d come crashing in through a window or something, with a bunch of other goblins. Doesn’t that sound fun?” - Excerpt from Vanishing Points 8.a
Titface is a Warrens Runner. A goblin princess specializing in the exploration, mapping, and nuances of the Warrens, she created her Demesne as something unbounded. Taking the largely unclaimed Warrens as hers, she leaves the Demesne undefended and free for others to take or alter as they see fit. For the most part, the oldest parts of it crumble beneath the weight of vandalism and the attentions of bottom-tier goblins as she claims new territory, making it hers with ‘Titface’ insignia graffiti and the help of her ‘crowd’. Her Demesne is fluid in a way a non-Realms practitioner could not manage, but the expansion of it is largely dependent on the existence, support, help, and goodwill of the crowd of goblins that follow her for her excellent parties and demeanor. It dwindles when she stumbles on an ancient goblin and twenty of her ‘crowd’ die, and it grows when she does something sufficiently wild or reckless. - quoted from Demesnes: A Place of One’s Own.