Chaos Cruiser
Making up the majority of Chaos fleets, Cruisers are medium-sized warships known for their speed and maneuverability. Able to function independently for long periods, Cruisers usually function as raiders for the Traitor fleets, striking deep into Imperial territory to cause havoc.
During fleet actions Cruisers will screen the approach of their fleet in conjunction with their Escorts. Once the battle starts in earnest however, these ships will join the battle line, and contribute their firepower to single out targets of opportunity.
Cruiser Classes
Carnage
Designed as support ships, the Carnage-class' role was to provide fire support for other ships with its long-ranged guns. The difficulty providing power to its weapons made it an object of contention within the Imperial Navy. It is considered an ill-starred design, and many ships of the class turned Traitor.
An Ordinance-boat, the Carnage was armed with mid and long-ranged Macro Weapons Battery broadsides, and carried another Macro battery on the prow.
Devastation
A Carrier class, the Devastation-class carries two Launch Bays, whichh are supplemented by long-ranged Lance broadsides, and a prow Macro Weapons battery. A fairly versatile and self-sufficient class.
Murder
Once the Cruiser of choice before the Lunar-class went into production, the Murder-class was armed by the best Plasma cannons that the Mechanicus could provide. Formidable at range, and equipped with powerful engines, a disproportionate number of ships of this class went Traitor in the millennia leading to the Gothic War.
The Murder is armed with powerful mid-ranged Macro plasma broadsides, while a long-ranged Lance battery is mounted on the prow.
Slaughter
The fastest Cruiser-class available to Chaos forces, the Slaughter-class gets its speed from the Scartix Coil, an experimental drive system. When one of the ships went Traitor, the engine designs were destroyed, leaving the Imperium unable to replicate it. Well, they can make the ship but not the plasma drive. However, it, like all knowledge, is in the Temple of All Knowledge on Mars due to how the Mechanicus works.
The Slaughter is armed with short ranged Lance and Macro cannon broadsides, and a Macro weapons battery mounted on the prow. Configured as a close-ranged brawler, the Slaughter takes advantage of its high speeds to close into its foes, unload its guns, then quickly escape any return fire.
In Battlefleet Gothic
Cruisers are the backbone of any player's fleet. Modestly-priced points-wise, there's enough variety among the ships available to Chaos to fill any fleet role. In general, Chaos Cruisers are much faster than their Imperial counterparts and, barring the Slaughter-class, have longer weapon ranges.
As with all things related to Chaos, Cruisers may be commanded by Chaos Lords, which grants access to Marks of Chaos. In turn, they can also be crewed by Chaos Space Marines for additional cost (which then allows access to Chaos Terminators).
A fleet can include up to a dozen cruisers as part of its list.
In Battlefleet Gothic: Armada 1 & 2
As a bit of a counter to Imperial vessels, Chaos Cruisers are much faster, and lean more toward longer-ranged attacks. Their Boarding capabilities are... decent, as far as Chaos goes, but don't write home about it.
That little detail aside, much like in the tabletop game, Cruisers are cheap and are used to mostly fill out your fleet list.