Other than the miner's cabins and lodges the only permanent structure in the area is Gloknier's Pit, a combination stable: inn, general store, town hall, and battle arena.
Personalities of Note
Silas and Sloan Crabtree - The fit, wild auburn-haired twins, Silas and Sloan, are beast tamers and hunters extraordinaire. Their trained bear, Thunder, is the current arena champion. Unbeknownst to anyone but the twins, they are Thunder. Born bearkin, the brothers have the supernatural ability to transform into bears. When Thunder has a match one brother pretends to be out hunting and transforms into Thunder, while the other acts as handler. Thus far, none are wise to the ruse.
Rowen Gloknier - This slick-tongued trader from Willsburg is the noble that funded the creation of the Blood Gravel Mine and built the fighting pit. He considers himself the benevolent lord of the area, though those that have earned his ire know he's not as noble as he pretends to be. Rowan lives in an elaborate suite in Glokneir's Pit.
AC 6  HD: 5 Attacks: 2 claws and a bite (1d6+1) or weapon (1d6+1) Special: See below Move: 8
Unless damaged by silver or magical weapons, bearkin regenerate, healing 3 hit points per round. On their turn a bearkin can forego all other actions and switch between its human and bear form. Unlike lycanthropes, bearkin cannot pass their condition on to others.
More information of the Portsmaw setting can be found here.
If you want to flesh out the fighting pits of Blood Gravel, I recommend +Jonathan Linneman's Underground Elemental Beastfighting posts.