IKC Negh’var
From Star Trek: Theurgy Wiki
The IKC Negh'var, as opposed to the IKS Negh'Var, was the Klingon Empire's Flagship as of March of 2381. It was a carrier, and High Chancellor Martok commanded it when he brought a fleet into the Azure Nebula, in hunt of the USS Theurgy.
The IKC Negh'var was destroyed in the Battle of the Apertures, where Chancellor Martok ended up fighting alongside the Theurgy to stop a Borg invasion.