In all the stories of battle and conquest, no one ever spoke to the House K'Valve, until after the War with the Dominion that is.
K'Valve was a house of nobles, technicians and engineers. Creating valuable items for the Klingon Empire they were very wealthy. They specialized in designs for transports, building replicators and terra-forming devices. It was very profitable just not as honorable as the many great warrior castes with a hundred kills under their belts or the explorer castes with a dozen conquests to boast of.
Some Klingons even referred to them as House Ferengi (But none of the Klingons who relied on them for exclusive access to the latest technology)
The House's patriarch, one JuQuar was traveling to meet with a Governor of an outlying world when his ship was set upon by 3 Dominion attack ships. With no defenses or fast impusle engines he was boarded, executed and the Industrial Replicators he was carrying were confiscated. The Jem Hadar destroyed his ship, but left more than enough evidence for Klingon investigators to piece together a chain of events.
Enraged, JuQuar's son Mok'Loar pulled all of their engineers off commercial endeavors and refocused them on making ships to fight the Jem'Hadar. Within 6 months, the "Fleetyards of K'Valve" had produced the K'Valve Class Cruiser. Sized somewhere between a Vor'Cha and K'Vort class, the K'Valve was a maneuverable powerhouse with one distinction in the entire Klingon Fleet. The ship used a new type of cloak that specifically fooled Jem'Hadar ships into thinking they were BREEN or CARDASSIAN.
The first ship, was sent to determine its capabilities and ability in combat not long after its completion. Mok'Lar cap[tained the ship, flying deep into the heart of Breen space, the ship encountered a cadre of Breen and Jem'Hadar vessels. Not only did it fool the Dominion ships, but the Breen as well. Using tetrion particles to block their weapons lock, the K'Valve locked torpedoes on all ships and opened fire, destroying 2 and crippling the remaining 4 vessels.
Still fueled with his desire for revenge, Mok'Lar destroyed the remaining vessels with the exception of one Breen vessel that they took in tow to study its offensive and defensive capabilities.
Following a successful test run and new found Breen tech, House K'Valve began mass producing their powerful ships and inserting them into key Klingon fleets. By the end of the war with the Dominion, House K'Valve had its fare share of Klingon Operas sung about its service to the empire.