- For other uses, see Krell.
In the year 2267, Krell commanded the IKS Korthos. His ship was dispatched to the planet Neural on a mission to upset the balance of power against tribal leader Tyree, by supplying one of his rivals with the "advanced technology" of flintlock muskets. Krell beamed down with two officers, Kragg and Mahtahk, but the three were attacked by mugato and only Krell survived. He chose to proceed alone on the mission. Krell eventually gained the support of Apella after Krell promised him that if he cooperated with the Klingons, then he would become leader of the planet, and in turn, Krell would establish a puppet government and form an alliance with the Klingon Empire. Unfortunately, Krell's plot was later foiled by Captain James T. Kirk and the crew of the USS Enterprise who supplied Tyree's tribe with similar weaponry. When Krell returned two months later to see both sides stalemated, he discontinued further military support of the villagers, satisfied that at least the planet was not controlled by the Federation. (TOS episode & Star Trek 10 novelization: A Private Little War; TOS - Klingons: Blood Will Tell comic: "The Order of Things"; WizKids module: Attack Wing)
Krell later established a 50-man outpost on Neural alongside the city of Victor, using a small spaceport to export leutrinium metal mined with slave labor. It operated for several years until Kirk convinced Apella and Tyree to order Krell and his Klingons to leave in the spring of 2273. (TOS novel: Serpents in the Garden)
By the early 2270s decade, Krell had risen to the rank of commander and served as commanding officer of a K't'inga-class battle cruiser. In 2273, Krell was ordered to proceed to Earth accompanied by two additional battle cruisers, the IKS Ravager and IKS Deathcry, and meet with the Federation Council and receive a detailed account about the destruction of the IKS Amar and two other cruisers during the V'Ger crisis.
En route, Krell's cruiser detected the newly refitted USS Enterprise warping out of the Sol system. Realizing the potential advanced technologies incorporated into the starship, Krell ordered his ships to pursue the Enterprise to the Scylla sector, where they ambushed the Constitution-class vessel and ordered Captain Kirk to surrender his ship. Unfortunately, Krell was forced to abandon the assault when the Enterprise tested the "omegatron device" on his ship and crippled her. (TOS - Untold Voyages comic: "Renewal")
- The Krell who appeared in TOS - Untold Voyages comic: "Renewal" wasn't associated with the Krell who appeared in TOS episode: "A Private Little War", but with no contradictory evidence, it has been assumed that they are the same person. The fact that Krell had cranial ridges in "Renewal" could be resolved by the fact that, like many QuchHa' Klingons, the cure that was developed in the 2270s was successful on him or he had ridges surgically added, as revealed in ST novel: Excelsior: Forged in Fire.
By 2287, Krell had risen to the rank of General and been placed in a position with Operations Command in the Klingon Defense Force. When the Galactic Army of Light terrorist group took the Klingon Diplomat Korrd hostage on Nimbus III, Krell ordered the IKS Okrona to free the hostages. Captain Klaa, the commanding officer of the Okrona, wondered why Operations Command would suddenly be worried about Korrd and Nimbus III. Klaa's Executive Officer, Vixis, recalled that Korrd's sister was married to General Krell. (TOS novelization: Star Trek V: The Final Frontier)
- TOS episode & Star Trek 10 novelization: A Private Little War
- TOS - Klingons: Blood Will Tell comic: "The Order of Things"
- WizKids module: Attack Wing
- TOS novel: Serpents in the Garden
- TOS - Untold Voyages comic: "Renewal"