Chaos Heavy Cruiser

Ancient grudges cut deep.

The Heavy Cruiser is a warship type originally used by the Imperium of Man, but now is primarily seen in the service of the Great Enemy. As an early attempt to create a cheaper and easier-to-maintain class of ships that could replace the Grand Cruisers, Heavy Cruisers try to capture the firepower of a Battleship on the smaller but swifter frame of the Cruiser.

Heavy Cruisers fell out of favor with Navy commanders due to the costs involved in maintaining their advanced systems. Their roles in fleets were soon filled by Battlecruisers, which were much economical to construct and easier to maintain due to using simpler technology.

Chaos has no such bias, and over the millennia ships of this type have made their way into Traitor fleets.

Interestingly, heavy cruisers (other than the Acheron) were not inherently flawed designs who mass-defected to Chaos. The Imperium merely stopped using them, so the only ones left in active duty are those that had turned to Chaos or been built by Chaos shipyards. GW only knows what idiot decided a set of very fast ships overflowing with macrobatteries or lances or attack craft was not worth maintaining. Especially since Chaos is infamously terrible at maintaining advanced technology, which means maintaining the ships’ systems was likely not difficult or could have been replaced in ships under construction with simpler, less advanced technologies.

Heavy Cruiser Classes

Acheron

Built on the Cardinal-class heavy cruiser hull which, interestingly, is the only keel-built Imperial ship still operating that fans know of. A testbed for experimental and possibly xenos-based technologies, only one was thought to have been built. Said ship suddenly defected to the side of Abaddon's forces during the Gothic War. Multiple ships of the same type were spotted since that time, which means that there's a Dark Mechanicus Forge World somewhere churning them out.

A dedicated Lance-boat, the Acheron-class features long-ranged Lance broadsides, a mid-ranged dorsal Lance battery, and mid-ranged forward-mounted Weapons battery

Hades

Near or far you'll die anyway.

The Ordinance-boat of the Heavy Cruisers, the Hades-class is equipped to engage opponents at not-quite brawling range. While it doesn't have the shields or armor to take a sustained firefight with larger ships, it's still more than a match of any Imperial Cruiser.

The Hades is the mirror of the Acheron, weapons-wise, with mid-ranged Macro Weapons Battery broadsides (despite its lowish shields and armor dor its size and so should be long-ranged all around) supplemented by a long-ranged forward-mounted Lance battery, and dorsal-mounted long-ranged Lance turrets.

Styx

I'm still much better than my replacement.

A Carrier-type, the Styx-class was eventually phased out in favor of the Mars-class Battlecruiser. Which of course makes no sense as the Mars carries far fewer attack craft and is generally considered a failed design. A versatile design, many Chaos Lords appreciate its ability to provide Fighter and Bomber support on top of its long-ranged weapons.

The Styx features a pair of Launch Bays, with a long-ranged Weapons Battery and long-ranged dorsal Lance battery. The long-ranged guns means that the ship can keep relatively out of danger while still being able to contribute the firepower of its weapons. More importantly (since the attack craft are the real power of this ship), it can blast the crap out of enemy escorts/raiders that try and make torpedo runs against it long before they get in range without having to re-direct its attack craft to protect itself while also being able to contribute a notable amount of firepower to assist friendly ships engaged with whatever.

In Battlefleet Gothic

Heavy Cruisers are a good source of firepower if Battleships or Grand Cruisers are unavailable for some reason (like lack of models). Barring the Styx, they're somewhat cheap points-wise, but always keep in mind that they're not any tougher than a regular Cruiser.

A Heavy Cruiser may be taken for every two Cruisers in a list. Like any other ship on the Chaos list, any one commanded by a Chaos Lord may select a Mark of Chaos, and gets the option of adding Chaos Space Marine crew for additional cost.

In Battlefleet Gothic: Armada 1 & 2

A slight upgrade over regular Cruisers, Heavy Cruisers feature better weaponry in exchange for a more limited selection of vessels. They're a smidgen more costly than a regular Cruiser as well, so they can't round off points as efficiently.

The roles of the three Heavy Cruisers available are clearly delineated, so it really falls under a player's preference how the ships fill their fleet list.