Star Trek: Forged in Fire

A book in the so-called Star Trek Novel Verse. It presents the expanded Backstory from the Star Trek Deep Space Nine episode "Blood Oath".

From the back cover: "A vicious pirate known as the Albino is cutting a deadly swath across space, creating turmoil in the Klingon Empire that threatens to spill into The Federation. But this criminal also has a secret that could shake the halls of Imperial power, and his genocidal plans against the race that bore him will have consequences even he cannot imagine, as several unlikely allies join swords to bring the Albino to justice: Hikaru Sulu of the USS Excelsior; Klingon captains Kor, Koloth, and Kang; and a hotheaded young Federation diplomat named Curzon Dax. Tempered in the flames of their shared adversity, a captaincy is forged, a blood oath is sworn… and a hunt begins that will stretch from one generation to the next."

This novel contains examples of:

 * Alternative Calendar: Klingon dates are frequently given alongside the human date.
 * Arc Welding: This novel ties Sulu's captaincy of the Excelsior (as seen in The Undiscovered Country and explored further in Star Trek the Lost Era) to the Blood Oath plot from Star Trek Deep Space Nine. In other words, Sulu's story arc is linked to that of Curzon Dax and the Klingon trio of Kor, Kang and Koloth. The novel also ties in the Klingon Forehead arc, from Star Trek Enterprise and Star Trek Vanguard. It's in this novel that the Quch'Ha plague is cured, allowing the affected Klingons to regrow their forehead crests. Kor, Kang and Koloth are among the Klingons who benefit.
 * Arch Enemy: Qagh to Kor, Kang, Koloth and Dax, as a result of the events of this novel.
 * Blood Oath: Given that the novel presents the Backstory to an episode entitled "Blood Oath", it's pretty inevitable.
 * Body Horror: The effects of the Omega IV virus and the engineered bioweapons Qagh creates from it. The Bajoran woman killed by a specifically-designed variant near the beginning of the novel is slowly dehydrated, as her body's water molecules are separated from the rest of her organic compounds.
 * Cold-Blooded Torture: Qagh inflicts it on the heroes in one scene.
 * Continuity Nod: This novel actually received a Continuity Nod before it was published. Long planned, its events were subtly referenced in The Sundered, a novel of Star Trek the Lost Era; this was several years before Forged In Fire was actually released.
 * Evil Albino: Qagh, who is often simply known as "the Albino". The label is justified in that there aren't any other Klingon albinos; they would be killed at birth. Qagh himself was left to die, before being rescued by Orions.
 * Evil Matriarch: Lady of the House Moj'ih would rather kill baby albino Qagh than allow his condition to bring shame to the family. Of course, she is following Klingon custom here; the Honor Before Reason nature of her culture blunts the individual evil to some extent. She still fits the trope though.
 * Explosive Leash: A variant. Qagh controls the men and women of his criminal organization through individually-tailored biogenic weapons. He can activate these if they get out of hand or attempt escape, painfully killing them.
 * Fantastic Caste System: As a result of the Quch'Ha plague (as seen in a two-part episode of Star Trek Enterprise season four) many Klingon families have lost their forehead ridges. A division between those who retained them and those who lost them has resulted in an unofficial caste system within the Klingon Empire. The ridgeless Klingons - the Quch'Ha, or "unhappy ones" - are somewhat undesirable in the social hierarchy. Some Quch'Ha disguise their status with artificial foreheads.
 * Fantastic Measurement System: A Kilaan is 22.5 minutes. There’s also the far smaller unit, tup.
 * Fire-Forged Friends: Well, obviously. It's in the title.
 * Foregone Conclusion: The tale's end is a matter of record; just watch the episode "Blood Oath". We know Qagh will escape, we know that the children of the three Klingon captains will be murdered, we know Curzon dies before they catch up to Qagh. Even those elements of the plot not connected to the episode are governed by this trope - Star Trek Generations and Star Trek the Lost Era make it clear Demora Sulu survives.
 * Hitman With a Heart: A variant. Do'Yoj is tasked with killing the infant Qagh, so as to conceal the shame of his albinism from the Klingon Empire. She refuses to go through with it; she just leaves him in the mountains instead. Of course, she expects this will kill him anyway, but at least her knife isn't tainted with a child's blood.
 * Hold Your Hippogriffs: "The Great Houses of the Council are balanced on a d’k tahg’s edge right now”
 * Infant Immortality: Averted. Daqs and the other Klingon children die. See Foregone Conclusion, above.
 * Like a Son to Me: Gannik, the Orion who found baby Qagh, insists the Klingon was like a son to him. An ugly, somewhat distasteful freak of a son, but nevertheless...
 * Military Maverick: Sulu.
 * My Greatest Failure: Dr. Antaak, the Klingon biologist from the Star Trek Enterprise episodes that resolved the Klingon forehead question, features in the novel (as does one of his direct descendants). The virus that caused the loss of a number of Klingon families' forehead ridges (the Quch'Ha' plague on Qu'vat) is Antaak's greatest failure, and the rest of his career, as well as his life, is dedicated to trying to undo the mistake. His attempt to put it right actually results in another plague, and the destruction of much of Qu'vat. This in turn ends up bestowing a generational My Greatest Failure upon his entire House, as in Klingon society children share in the honour or dishonours of their parents.
 * Nakama: Kor, Kang and Koloth seem to have become this, even before the mission against Qagh. Kor and Kang open fire on other Klingon ships that attempt to destroy Koloth's vessel as part of quarantine protocols.
 * The Obi-Wan: Sarek, to Curzon Dax.
 * Pet the Dog: Klingon ambassador Kamarag, who is usually presented as an Ass in Ambassador, has a Pet the Dog scene in this novel. He defends Sulu's Military Maverick actions at a Starfleet hearing, probably helping save Sulu's career.
 * Revenge By Proxy: Qagh, on Kor, Kang, Koloth and Sulu. He targets their children with tailored bioweapons, and succeeds in killing the first born of the three Klingons. Sulu's adult daughter survives (see, Foregone Conclusion).
 * Unfortunate Name: "Qagh" is tlhIngan Hol (Klingon) for "mistake".
 * With Friends Like These: Dax and the three Klingons.
 * You Have Outlived Your Usefulness: Qagh frequently treats his subordinates like this.