Background:

Goblins:
Goblins are short, sneaky creatures of a semi subterranean lifestyle.
Average Height: 3-4 feet
Hair colour: any
Eye colour: any
Skin colour: Greens and browns are most common, although some red, blue and even purple tones have been seen on occasion.
Level of technology: Medieval level of development, although goblins are clever with the use of clockwork and some alchemy. Blackpowder weapons do exist, but are rare and notoriously unreliable. Most goblin weapons, buildings, clothing and other artefacts are in slight disrepair, or hastily fixed.
Style of dress: Goblins are very eclectic, appropriating or outright stealing modes of fashion from other races and each other. There are numerous tribes all over the world, with a variety of tastes and influences.
Personalities: Goblins have several overriding personality traits that are seen in varying degrees across the species. They are sneaky, untrustworthy, cowardly, and selfish. They are also very curious, inventive, and resourceful.

The Goblin Kingdom
The kingdom is located inside the Black Tooth Mountain, a craggy peak of dark stone. The interior of the mountain abounds with odd rock formations, treacherous terrain, many species of fungi, and numerous dangerous creatures. The goblins live in fortified cave networks midway up the mountain ranging from vaulted chambers able to comfortably house thousands, to tiny crawlspaces barely large enough for a goblin.
The competition itself will take place in the labyrinthine caverns below the kingdom.

The Story So Far:
The Goblin king is dead. The how and why of his death is not clear, which is often the way for goblin monarchs. What is clear is that he has left no clear heir to the throne; all his near family killed in a tragic cave in. However, as a well-travelled king, he "put it about" a lot. I mean a LOT! Every two bit, ambitious goblin that can trace their lineage back to the deceased monarch is now converging on the kingdom in an effort to claim the throne for themselves. In order to deal with this horde of aspirants, the chief shaman, Thugglewick the Creepy, has invoked the ancient goblin tradition of the "Underchallenge". This is where all those wishing to be crowned king will descend into the caverns below the kingdom, to compete in a winner takes all challenge, where the first to defeat their enemies and emerge alive will be crowned king.