The IKS Negh'Var was the massive flagship of the Klingon Empire in the 2370s, from which Gowron and Martok directed the assault on Deep Space Nine in 2372.
The Negh'Var is the lead ship of the Negh'Var class, the largest Klingon warship of its day. It is introduced in the Deep Space Nine episode The Way of the Warrior, in which Chancellor Gowron and General Martok command it during the invasion of Cardassia and then the attack on Deep Space Nine, breaking off only when Starfleet reinforcements approach.
The design was first seen as a Klingon attack cruiser of a possible future in the Next Generation finale All Good Things. A much larger mirror-universe counterpart serves as the Regent's flagship in Shattered Mirror, where it is driven off by the rebels' Defiant.
The class went on to appear in fleet scenes throughout the Dominion War.