Korax

Korax was a Klingon officer who served the Empire during the 23rd century.

Guardian of Forever

In the 2260s, Korax was first officer of the IKS Gr'oth under Captain Koloth. (TOS episode: "The Trouble with Tribbles" and TAS episode "More Tribbles, More Troubles")

However, Korax eventually fell out of favor with the Empire, and by 2287 was running an obscure dilithium-mining prison on Pao'la. (TOS novel: In the Name of Honor

Alternate Timelines
In an alternate timeline, Korax became Captain of the G'roth and in 2270 attacked what he suspected of being a Federation super-weapon development site. He plunged his ship directly onto the supposed site, vaporizing the Guardian of Forever. (TOS novel: Provenance of Shadows)