In the 23rd century, the House of Mo'Kai was infamous for being composed of "watchers," "deceivers," and "weavers of lies" – employing tactics of espionage and subterfuge that other Great Houses considered dishonorable compared to a frontal assault. (DIS: "The Butcher's Knife Cares Not for the Lamb's Cry")
L'Rell's mother was born to the House of Mo'Kai while her father was of the House of T'Kuvma. She considered herself to be part of both Houses. (DIS: "The Butcher's Knife Cares Not for the Lamb's Cry")
In 2256, Ujilli, the representative for the House of Mo'Kai on the Klingon High Council, led a vessel among a Klingon fleet that answered the signal from the Beacon of Kahless. While hearing T'Kuvma lay out his desire to unite the Klingon people, the House's representative was keen to hear more. (DIS: "Battle at the Binary Stars")
During the first months of the Federation-Klingon War, the House of Mo'Kai was nominally independent. In December of 2256, they and the House of D'Ghor secretly arranged a meeting with Vulcan to discuss the possibility of uniting against Kol's forces. However, the meeting was in fact a ruse by Kol to capture a high-ranking Federation official. As reward, the House of Mo'Kai was officially welcomed into Kol's unified Klingon Empire, and furnished with cloaking technology. (DIS: "Lethe")
When Ujilli's niece L'Rell declared herself to be the new Chancellor of the Klingon High Council, the House of Mo'Kai became her close supporters. In 2257, Ujilli was murdered by followers of Kol-Sha of the House of Kor who attempted to usurp power from L'Rell. (DIS: "Point of Light")
In a holoprogram created by the Hirogen in 2374, the Klingon character of Kathryn Janeway was from the House of Mo'Kai and claimed, while fighting an Alpha Hirogen, that the House would never yield. (VOY: "The Killing Game")
|Klingon Great Houses|
|Antaak • D'Ghor • Duras • Grilka • Konjah • Kor • Korath • K'toh-maag • Martok • Mo'Kai • Mogh • Noggra • T'Kuvma|
Mirror universe: Duras
The spelling of "Mo'Kai" is from the Star Trek Encyclopedia; according to the script for VOY: "The Killing Game" (dated 18 November 1997), the House was originally called "Tokath". The English subtitles for DIS: "Battle at the Binary Stars" use the spelling "Mókai", while the Klingon subtitles use "mo'qay".
According to the background of Star Trek Online, the House of Mo'Kai was dissolved in 2389, following the deaths of all its members at the hands of B'Vat (β). House Mo'Kai re-emerged some two decades later when J'Ula (β), matriarch of the House and elder sister of T'Kuvma, was temporally displaced from 2256, during the attack on Starbase 1, to around 2409-10, the setting of Star Trek Online. J'mpok (β), the Chancellor of the Klingon High Council, feared that the return of J'Ula and House Mo'Kai would result in civil war, which ultimately began following a confrontation with J'Ula and her loyalists (which included Klingons of the modern era) in the Great Hall on Qo'noS.