Kian was a 23rd century Klingon indivdiual who served the Klingon Empire's Defense Force as an officer.
Kian was an ensign, serving under the command of Captain Krenn in the 2230s aboard IKV Fencer. Kian was assigned by Krenn to lead a boarding party to a Willall starship (unnamed starships) captured by Fencer. When Fencer was recalled to Klinzhai, Kian was quite eager to remain on the prize ship and have the party pilot the ship to base under his command. Krenn was initially reluctant, but was impressed by the young ensign's initiative, and granted Kian his first command.
Years later, in the 2240s, Kian had attained the rank of captain and was the commander of IKV Fury. Kian's squadron was issued secret orders by conspirators attempting to sow distrust between Klingons and the Federation. Per these orders, Kian, accompanied by manipulative Security Commander Merzhan, was en route to attack the Federation colony of Serkash II. When Krenn discovered the plan from Federation conspirators who were complicit in allowing their own citizens to be slaughtered for politics, he decided to intercept the dishonorable attack with his cruiser, IKS Mirror. Krenn regretted killing his former ensign, but recognized the need to stop the dastardly plan. Kian died in his command chair, as visible to Krenn's bridge, when Merzhan broadcast Fury's final message before Kian's vessel was destroyed. (TOS - Worlds Apart novel: The Final Reflection)