The Varduun are the only major merchant clan that is also a city-state. They make up nearly the entire mountainous province of Nakkim, and consist mainly of Dwarves, Dragonborn and Half-Orcs.
They are called War Drums, and they don’t just specialize in war, they exclusively cater to it. They supply arms, armor, munitions, siege-weaponry- everything but troops- all to whomever can pay. They have no problems with arming both sides of a conflict!
Every century or so, when the previous example has been forgotten, some group or city-state tries to raid a Varduun shipment. The Varduun have the secret of explosives, though, and- expensive enough, in lives- if an enemy fights their way through the heavy guard; the Varduun caravaners will destroy their wagons rather than let them be taken. This is swiftly followed by a retaliatory strike- the Varduun march down from their mountains and decimate everyone aligned with the attackers.