Chaos Grand Cruiser
Grand Cruisers are a type of warship that carry the firepower of a Battleship on the smaller but much swifter frame of a Cruiser. Due to the complex systems needed to build such craft, the Imperium no longer makes Grand Cruisers, but a few still remain in the Imperial Navy's service in Reserve fleets.
Many Grand Cruisers had gone over to the service of Chaos over the millennia due to one reason or another. Due to their combination of raw firepower and speed, these ships are favored by many Renegade commanders.
Grand Cruiser Classes
Repulsive
Originally known as the Corinus-class, these ships entered Chaos use when the Death Guard captured several and returned with them to the Eye of Terror. When corrupted variants appeared afterward, Imperial scholars reclassified the class as the Repulsive instead.
The Repulsive is armed with front-mounted Torpedo launchers and short-ranged Lance turrets, as well as mid-range broadside Macro batteries. Coupled with its heavy armor and shields, this means that the Repulsive is more than capable of surviving close-ranged firefights and meting out pain in return.
Retaliator
A Carrier-type, the class had been in service of Chaos since at least M35, when an entire squadron of ships mutinied. The Retaliator carries four Launch Bays, plus mixed Macro and Lance broadside guns. The design intention is pretty clear as it lacks firepower. Against large ships use fighters and bombers to cripple enemy firepower and communications and engines while pounding at their shields. Then either kill it over a long period of time or ignore the de-fanged foe. Against smaller ships, basically the same but with the firepower to quickly kill them while the attack craft do other things instead of engaging those ships.
While in-universe lore describes the Retaliator as a "Master of None" type of ship (versatile, but doesn't excel at all at any one role), the Battlefleet Gothic: Armada games decide to give the class short-ranged mixed broadsides instead. This not only limits its damage output, puts it in an odd spot of being a Carrier that has to close in to even use its guns.
Executor
The dedicated Lance-boat of the Grand Cruisers, the firepower that the Executor could put out was much appreciated by Imperial Navy commanders. The last squadrons of this class vanished pursuing raiders close to the Cadian Gate, only to reappear under Renegade control some five hundred years later.
The Executor comes with a mix of short-ranged and mid-ranged Lance broadside batteries as standard. In the Battlefleet Gothic: Armada games, this gives the class incredible accuracy, in return for having a relatively narrow firing arc.
In Battlefleet Gothic
Chaos Grand Cruisers fill the need of a quick platform capable of putting out the firepower and having almost the durability of a Battleship. These are also much cheaper points-wise, and can be used to anchor a Chaos list if there aren't a lot of points to spare.
A Grand Cruiser may be taken for every two Heavy or regular Cruisers in a fleet list. If commanded by a Chaos Lord, a player may select any of the four Marks of Chaos available.
In Battlefleet Gothic: Armada 1 & 2
Like their Imperial counterparts, Chaos Grand Cuisers provide a cheaper alternative to Battleship in fleet composition. That said, barring the Repulsive, the relatively short ranges of the other classes leave some players scratching their heads, as they go against the trend of long-ranged firepower for Chaos warships.