A loose alliance of convenience exists between Zaun's powerful Chem-Barons, powerful individuals who each control an area of the city. They are factory owners, business owners, landlords, resource owners, and/or mob/gang bosses having large amounts of money, man power and influence. It is they and their thugs who keep Zaun from descending into chaos.
A Baron who could afford high grade chem-tech. Was defeated by Urgot. (Deceased)
A Baron who terrorized the gutters of Zaun. He had planned to marry Lady Sofia of Clan Arvino so that he would inherit her clan's wealth and influence in Piltover. He was successfully stopped by Camille of Clan Ferros. (Deceased)
Grime lost both his arms in an explosion at one of his chem-refineries. Despite (or perhaps because of) this, his chemtech stock is some of the most sought after blends.
Takeda is a a Chem-Baron with a notoriously violent temperament, reputation for bloody gang warfare and has made no secret of his disdain for his fellow chem-barons. Claiming lineage from an exiled caste of warriors from a distant land, he has plans far beyond his own territories and interests. One example of such plans was the Zaun Amorphous Combatant.
A chem-baron with many business interests in Piltover, Lenare deals mainly in research into golem technology. Her ravaged body was dying, so she had her head transplanted to a hextech-powered replacement. She visits Piltover regularly for fluid baths, and blood/oil transfusions.
Baron Voss was the warden of the Dredge, a chemtech prison mine beneath Zaun. She would sometimes offer freedom in return for a prisoner's tortured confession - granting it with the edge of her blade. Voss however fled to the surface after an encounter with Urgot, who took control of the mine in her place.
Once a lowly lieutenant, Spindlow murdered his boss and took over his empire. Armed with a pair of shock-batons, he is a ruthless killer who sees murder and mayhem as tools of the trade.