Imperial Battleships
Pride of the Fleet
Emperor Class Battleship

Size: 8.5 KM long, 3.1 KM abeam at the wings (can vary massively, different battle fleets and even fleet admirals refitting and purpose-building unique and highly customised warships)
Crew: 220,500
Max Acceleration: 1.6 g
Defences: Tripple-armoured prow, faramite-alloy armour plating, 8 battleship class Void shields.
Standard Main Armament: 8 Heavy 'Titan Forge' Macro Cannons (4 per broadside), 4 hangar decks (2 per broadside), 5 Heavy Macro Turrets (dorsally mounted)
Standard secondary Armament: turbolasers, missile banks and autocannons (belly and spine mounted, undetermined numbers)
Auxiliary craft: 4 Arvus lighters, 1 Apulia lander, 2 Tetrarch assault-landers, 4 Devourer Drop ships, 40 Thunderbolts, 30 Marauders, 20 Valkyries, 12 Vultures, 110 Furies, 40 Star Hawks, 12 Shark Assault Boats
Lore: This warship has been the pride of Imperial fleets for over ten thousand years and has served the Imperium as the mainstay and flagship of nearly every major fleet. The large number of massive Heavy Macro Cannons powered by huge plasma reactors able to propel the immense projectiles far beyond the range of most cruisers and Battle cruisers and smash them into unrecognisable burning hulks; and great swarms of strike craft able to choke any attempt by smaller vessels to destroy the ponderous warship as well as reach out and strike fleets from frightening ranges due to the advanced long range auspex.
The Emperor Class is commonly used to bring powerful re-discovered colonies and rogue human empires into line with Imperium: able to choke the atmosphere of planets with swarms of hundred-metre-long bombers and masses fighters; the massive imposing shape blotting out the sun above the planet's capital from low orbit as it destroys whole fleets of lesser warships at the head of an Imperial fleet.
The battle honours claimed by the Emperor class are beyond counting: having served a major flagship role in nearly every major conflict in the Imperium for over ten millennia, the Gothic War was no exception. Lord Admiral Von Ravensburg, commander of Battlefleet Gothic, led his Battlefleet against Abaddon from the bridge of the ancient Emperor class warship the Divine Right. The Divine Right had already achieved legendary status before the war: lost in the Warp during the Horus Heresy, found thousands of years later fused with an ancient Chaos space hulk, somehow still battle-ready and uncorrupted by the taint of Chaos. The warship displayed an incredible resistance to Chaos weaponry, and with its power Von Ravensburg ultimately broke the backbone of Abaddon's armada at the Battle of Gethsemane. It was there that the Divine Right led the battlefleet directly into the centre of the Chaos formation, destroying several of Abaddon's largest warships and forcing a retreat straight into a carefully prepared Eldar ambush. The Divine Right not only survived the battle, but led from the front without receiving critical damage. She and her Admiral pursued the Warmaster and his defeated fleet to the Schindlegist system where she would destroy many more of Abaddon's ships using her massive Macro Cannons.
The ship continues to serve as Battlefleet Gothic's flagship: the ship's renown being such that a monument to the vessel was built on Holy Terra, next to a statue of her Captain; Von Ravensburg, and inscriptions of the names of all those who served with the Battlefleet (from Von Ravensburg himself to the lowliest merchants).
Retribution Class Battleship

Size: 8 KM long, 2.9 KM abeam at the wings (can vary massively, different battle fleets and even fleet admirals refitting and purpose-building unique and highly customised warships)
Crew: 195,500
Max Acceleration: 2.1 g
Defences: Triple-armoured prow, faramite-alloy armour plating, 8 battleship class Void shields.
Standard Main Armament: 24 Heavy 'Titan Forge' Macro Cannons (12 per broadsides), 5 Heavy Lances, 6 super heavy torpedo launchers.
Standard secondary Armament: turbolasers, missile banks and autocannons (belly and spine mounted, undetermined numbers)
Auxiliary craft: 4 Arvus lighters, 1 Aquila lander, 1 tetrarch assault-lander, 2 Devourer drop ships
Lore: This Battleship is the purest expression of what the term Battleship is intended to mean, with unmatched fire-power and immensely thick armour and shielding. This Battleship is the battleship of the Imperial Navy. This Class of warship is the backbone, and muscle, of the Imperial Navy: having the most armour and most ferociously powerful broadsides of any class in the Imperial Navy (which are both impressive claims given the competition), very few classes in any Navy able to challenge her power in a gunnery duel. The Retribution is the ultimate expression of Imperial ship-building process, being the absolute zenith and purest incarnation of Imperial Naval doctrine, standing for everything the Imperium values most in a vessel: firepower and protection.
The ship's armament is an all-big-gun layout of Heavy Macro Cannons (an impressive 12 of the huge cannons per side), 5 dorsal lances to fend off escorts and finish off crippled opponents and a group of huge torpedo launchers, able to cripple any other other capital ship with one massively devastating hit. The ship also boasts an impressive power plant, which allows it to boost the range of the cannons and lances beyond the reach of most Battle Cruisers and Cruisers. The ship's tactical application is simple, unchanged for millennia, and terrifyingly effective. The ship closes with its enemy, firing a swarm of massive torpedoes into the mass of enemy vessels, the massive adamantine prow and multiple thick layers of shielding protecting against all but the very heaviest of enemy fire: and then opening with a devastating barrage of Heavy Macro Cannon fire, crippling or destroying anything unlucky or foolish enough to find itself in the path of the broadside. The ship is also the backbone of any large battle line, providing the heaviest fire support and the most well protected hull to the line of warships.
The warship has seen service in nearly every major Imperial conflict for over ten millennia, alongside her sister class the Emperor Class, and earned great renown and a fearsome reputation from countless battles. Battlefleet Gothic, like all major Battle Fleets, fielded several these Battleships in fleet formations. Battlefleet Gothic's Retribution battleships were all ancient warships, dating back to the earliest days of the Imperium: one of them, Blood hawk, had served against the largest Ork Waaagh in history lead by the legendary Ork Warboss 'The Beast', served during the Age of Apostasy as well as serving loyalist forces in the Horus Heresy. These venerable vessels proved devastating wherever they engaged, dominating the flow of the battle as their heavy broadsides tore apart Battleship and Cruiser alike.
Apocalypse Class Battleship

Size: 8.3 KM long, 3 KM abeam at the wings (can vary massively, different battle fleets and even fleet admirals refitting and purpose-building unique and highly customised warships)
Crew: 200,000
Max Acceleration: 1.9 g
Defences: Triple-armoured prow, faramite-alloy armour plating, 8 battleships class Void shields.
Standard Main Armament: 6 Heavy Plasma Lance Batteries (3 per broadside: 6 eight-barrelled turrets per broadside), 5 Heavy lance turrets (dorsally mounted), Prow Nova Cannon
Standard secondary Armament: turbolasers, missile banks and autocannons (belly and spine mounted, undetermined numbers)
Auxiliary craft: 4 Arvus lighters, 1 Aquila lander, 1 tetrarch assault-lander, 2 Devourer drop ships
Lore: This vessel is a terrifying opponent to behold, able to reduce whole fleets to chunks of molten slag in an incredibly short period: the awesome power and increasing rarity of the ancient vessel making her a highly sought after Battleship by many Admirals of the Imperial Navy. This warship is the sniper and heavy fire-support battleship of the Imperial navy.
This warship is truly an Ancient design, the ship pre-dating the Horus Heresy by at least a millennium, best estimates putting the original designs age as far back as the beginning of the Great Crusade and the birth of the Imperium of Man. The ship is a rare gem in the Imperial Navy, production of the Mighty vessel no longer possible, much of the technology and means of production for the ship being since lost in the mists of time: this makes the ship highly prized and a great loss to the Imperium if lost (the Class being named 'The Queen of the Void'). Many attempts have since been made to try and replicate the vessels might, but most have failed horribly. The ship class herself is an awesomely powerful Battleship, being equipped with a Nova cannon and a vast number of long range lances, having firepower in one broadside comparable to the Retribution Class: however, a slow rate of fire means that Retribution keeps the crown for most powerful broadsides. However, the lances prove to have various strengths over the more common Macro broadsides: they are more accurate (meaning they are devastating to escorts and light cruisers), they ignore heavy armour and are more effective vs void shielding (meaning that battleships have much to fear from an Apocalypse's broadside) and the Nova cannon is the perfect weapon for dealing with any escapees or for causing mass destruction and confusion as the Battleship closes in on her prey.
The Battleship, despite the increasing rarity of the Class, can be found in service with nearly every major Battle fleet: able to reduce any enemy fleet to a collection of burning hulks in seconds (with only a relatively small escort required to protect against strike craft). Despite this, the Battleship did not reportedly take part in the Gothic War, but is a popular (and surprisingly common) warship with Battle fleet Armageddon: serving as a perfect counter to the escort heavy, short range and tough armour of Ork fleets; the large number of lances carving through their heavy armour from far outside their effective engagement range.
Oberon Class Battleship

Size: 8.3 KM long, 3 KM abeam at the wings (can vary massively, different battle fleets and even fleet admirals refitting and purpose-building unique and highly customised warships)
Crew: 202,800
Max Acceleration: 1.9 g
Defences: Tripple-armoured adamantium prow, faramite-alloy armour plating, 8 battleship class Void shields.
Standard Main Armament: 8 Heavy 'Titian Forge' Macro Cannons (4 cannons per broadside), 2 Hangar decks (1 per broadside) 2 Heavy Plasma Lances (1 per broadside), 5 heavy lance turrets (dorsally mounted), 6 torpedo launchers
Standard secondary Armament: Turbo lasers, missile banks and autocannons (belly and spine mounted, undetermined numbers)
Auxiliary craft: 4 Arvus lighters, 1 Aquila lander, 1 tetrarch assault-lander, 2 Devourer drop ships, 40 Thunderbolts, 30 Marauders, 10 Valkyries, 6 Vultures, 55 Furies, 20 Star Hawks, 6 Shark Assault Boats
Lore: This ship is believed to be as old as the Apocalypse Class, having no dedicated Imperial shrine (like the Apocalypse) given its more secular history. The ship is also widely believed to be the ship that the Emperor class was built from (having suspiciously similar interiors and auspex equipment) but the exact age, purpose and origin of the design is shrouded in mystery. The ship also becoming increasingly rare, production of the vessel having long-ago ceased in favour of her successor the Emperor Class.
The Oberon Class herself is a swiss army knife among battleships, having at least one battery of all standard Imperial weapons used in the Imperial navy: a Launch Bay, a Lance Battery, a Battery of Heavy Macro cannons, Torpedo Launchers and Dorsal Lances.
This gives the Oberon options, a lot of options, for dealing with just about any enemy a battleship may face: sending a mixed assault of torpedoes, Macro cannons shells, lance bolts and strike craft which is very hard for any-one adversary to defend against alone. The ship also features advanced auspex sensors: allowing the ship to detect incoming enemies and launch a retaliation strike, from whatever of her weapon systems are in range, before they are even aware of the Battleships presence.
This combination, together with the trademark heavy Imperial Battleship armour, makes the Battleship perfect for long range patrols, heavy escort duty and small-scale engagements: able to remain self-sufficient for extended periods of time, with minimal escort required, able to deal with any adversary she may run into.
However, this versatility is also her biggest weakness.
She can't produce the swarms of fighters that an Emperor or Nemesis can, match the awesome raw firepower of the Apocalypse or Retribution or even hope to hold a candle to the insane speed of the Invincible class. This has lead the Oberon to be rarely seen in major fleet engagements in the Imperium: often being held in reserve to scout out dangerous or contested areas of space, provide heavy escort to critical convoy operations and take part in extended patrols in occupied space for enemy threats.
Oberon Class battleships did see serve with Battlefleet Gothic in the Gothic War filling these roles, but never took part in any of the main fleet engagements: seen as an inferior choice to the Retribution for line combat, and less effective in flagship duties when compared to the Emperor.
Invincible Class Fast Battleship

Size: 8 KM long, 2.9 KM abeam at the wings (can vary massively, different battle fleets and even fleet admirals refitting and purpose-building unique and highly customised warships)
Crew: 200,000
Max Acceleration: 4.3 g
Defences: Triple-armoured prow, faramite-alloy armour plating, 6 battleships class Void shields.
Standard Main Armament: 24 Heavy 'Sun Breaker' Laser-Macro Cannon (12 per broadside), 5 Heavy Laser Lance turrets (dorsally mounted), 6 torpedo launchers
Standard secondary Armament: turbolasers, missile banks and autocannons (belly and spine mounted, undetermined numbers)
Auxiliary craft: 4 Arvus lighters, 1 Aquila lander, 1 tetrarch assault-lander, 2 Devourer drop ships
Lore: This warship is the brain-child of Admiral Kisher, of Battlefleet Tempestus, in early M38.
The admiral was a very frustrated man. He was tired of Ork pirates, Heretical raiders and Eldar corsairs constantly slipping inside the borders of the Imperium and reaping havoc on supply convoys: and then the Imperial fleet being unable to chase down and catch the assailants without suffering casualties. The Invincible Class was Kisher's answer to 'The Pirate Problem'. The ship combined the fearsome firepower of the Retribution, with the speed and mobility of a light cruiser.
The concept of how the ship would perform was quite simple: the battleship would hunt in packs, with a small escort of light cruisers for dealing with any close-in opponents, and destroy roving pirates and raiders. The ship could also mercilessly chase down enemy light cruisers and cruisers, attempting to escape after a raid of on friendly convoys.
The ship did however have one serious flaw: her armour.
Despite being frequently told that the massive power conduits that powered the ship's propulsion were too poorly protected, and being recommended to go with a smaller power-plant by many magos within the Mechanicus, Kisher (and his supporters) wouldn't do anything to the design if it sacrificed speed. The result was the Warship being very poorly armoured for an Imperial Battleship, having armour that would normally be found on an Imperial cruiser.
This, together with its similar appearance to the more common and well-known Retribution Class, meant that many admirals employed the ship like a retribution in the main line of battle with disastrous results. This lead to widespread disillusionment with the design, the Invincible Class vessels being referred to as 'Kisher's Kombustibles'.
However, when used in her intended role and as a heavy escort, she was devastatingly effective.
One Eldar fleet came across a group of 4 Invincible Class vessels patrolling in the Tempestus sector. The Eldar captain seeing what was in front of him as a gift, mistaking the 4 Invincibles for 4 Retributions caught without their escorts (as the Invisible does look similar to the Retribution), believing the cumbersome vessels would be unable to react and catch his much more nimble ships.
The Eldar captain launched the surprise attack, destroying the light escort compliment and damaging the starboard batteries on one of the Invincibles, and then breaking off to make another run... only to discover in horror that the huge Imperial vessels were keeping pace with his ships and slowly destroying them under massed Heavy Laser-Macro Cannon fire.
Caught off guard and desperate to regroup and re-assess the situation the Eldar attempted to retreat, only to be relentlessly pursued by these surprisingly nimble Imperial Battleships. Unable to run, and with no clear edge over the larger warships, the Eldar were slaughtered to the last under a barrage of Heavy Macro fire.
This, alongside other examples of the previously ridiculed warships destroying the Imperium's enemies, now making it a firm favourite of Admiral Knightsbridge and his followers. Adopting and modifying the design to be the ultimate climactic design and flagship for their anti-piracy fleets in M41.
Nemesis Class Fleet Carrier

Size: 8.5 KM long, 3.1 KM abeam at the wings (can vary massively, different battle fleets and even fleet admirals refitting and purpose-building unique and highly customised warships)
Crew: 250,000
Max Acceleration: 1.6 g
Defences: Tripple-armoured prow, faramite-alloy armour plating, 8 battleship class Void shields.
Standard Main Armament: 6 hangar decks (3 per broadside), 5 Heavy Laser Lance Turrets (dorsally mounted)
Standard secondary Armament: turbolasers, missile banks and autocannons (belly and spine mounted, undetermined numbers)
Auxiliary craft: 4 Arvus lighters, 1 Apulia lander, 2 Tetrarch assault-landers, 6 Devourer Drop ships, 40 Thunderbolts, 30 Marauders, 20 Valkyries, 12 Vultures, 185 Furies, 56 Star Hawks, 24 Shark Assault Boats
Lore: Despite being a relatively new design, predominantly seen in service with Battlefleet Gothic in M41, the Nemesis Class origins can be traced back to M36 with the 'Gareox incident' in Battlefleet Bakka. The 'Gareox incident' was a series of fleet exercises with Battlefleet Bakka, between the 'Young school' Admirals and the 'Big-Gun lobby' admirals, to prove the combat effectiveness of their fleet concepts and designs (diplomacy and politics having broken down after a millennia of stalemate) and was effectively an Imperial Civil-War in the Bakka sub-sector. The 'Young school' where insistent that Battleships and macro cannons were obsolete, fast attack carriers and long range lances where the way forward for the Imperial Navy. However, the combat saw the tried and tested Imperial designs winning out over the experimental Despoiler Class the younger Admirals had created, the Emperor class proving vastly as both a battleship and carrier. Bitter, with their reputation destroyed among the Imperial Admiralty and with the threat of charges of Heresy for their unauthorised ship design: the desperate admirals handed their service and remaining 3 Despoilers to Chaos.
One of their early proposals (before they created the Despoiler Class and turned to chaos) was to have the Emperor Class converted into a dedicated carrier, removing the Heavy Macro cannon turrets and batteries for more hangar bays and Dorsal lances, the Emperor class would then also have a surplus of energy to greatly improve speed and lance range.
This obviously repulsed by the Big-Gun lobby, who stood by and supported the old Imperial designs, being fans of line-combat and broadside warfare.
However, later experiences from the Gothic War and First Tyrannic War would present the need for a dedicated fleet carrier, and (despite the design origin, and heavy stigma still placed one the ship among the admirals of Battlefleet Bakka, who protest the vessel is an affront and betrayal to the Imperial Navy) the Emperor class conversion into Nemesis Class carriers began with Battlefleet Gothic, Tempestus and Calixis in M41.
Nemesis herself had exactly the effect that her supporters had been hoping for, able to throw up vast swarms of fighters to swamp and overwhelm enemy fleets from extreme range, and long range dorsal lances for fending off closing escorts.
She does require a heavy escort, another battleship, a Battlecruiser or a detachment of cruisers: but the advantages she provides over Tyranid and pirate threats are enough to cement the Nemesis as a favourite among some battle fleets in the Imperium.
Victory Class Battleship

Size: 8 KM long, 2.9 KM abeam at the wings (can vary massively, different battle fleets and even fleet admirals refitting and purpose-building unique and highly customised warships)
Crew: 200,000
Max Acceleration: 2.1 g
Defences: Triple-armoured prow, faramite-alloy armour plating, 8 battleships class Void shields.
Standard Main Armament: 6 Heavy Laser Lance Batteries (3 per broadside: 6 eight-barrelled turrets per broadside), 5 Heavy Laser Lance turrets (dorsally mounted), Prow Nova Cannon
Standard secondary Armament: turbolasers, missile banks and autocannons (belly and spine mounted, undetermined numbers)
Auxiliary craft: 4 Arvus lighters, 1 Aquila lander, 1 tetrarch assault-lander, 2 Devourer drop ships
Lore: The Victory Class is believed by many to be a modified Retribution Class Battleship, having largely similar layouts internally and externally, but with an all-lance armament as opposed to the more standard Macro Cannon Batteries. The most commonly believed reason for such modifications being to replicate the massively successful Apocalypse Class Battleship. These ships are all also extremely old. How old is unknown due to the stubborn refusal of Mars to share their records of the ship, but Conqueror at least is known to have to have lead the unification/crusade fleet that ended the age of strife in the Tempestus Sector during the Great Crusade: essentially being one of the ships present at the founding of Battlefleets Temestus and Bakka and the birth of the Imperium.
Only 4 of these ships are known to be in service, all with Battlefleet Bakka: Victory, Argus, Conqueror and Hammer of Scaro (the only ship of the class to have 9 Torpedo launchers as opposed to a Nova Cannon). All these ships seeing service during the First Tyranic War in the defence of Macrage against the Tyranids.
The Victory Class with their long-range lances and Nova Cannons proving exceptionally deadly against the massed swarms of biological tyranid vessels, many of the tyranids being literally cooked alive by the blast from the Nova Cannons and Lance bolts, their fire-power and armour protection allowing all 4 to survive the intense series of fire fights that ensued in the Ultramarine sectors.
All 4 Victory Class warships are currently undergoing crew retraining and rearmament in preparation for further service with Battlefleet Bakka.
Vanquisher Class Battleship

Size: 8.3 KM long, 3 KM abeam at the wings (can vary massively, different battle fleets and even fleet admirals refitting and purpose-building unique and highly customised warships)
Crew: 205,000
Max Acceleration: 1.9 g
Defences: Tripple-armoured adamantium prow, faramite-alloy armour plating, 8 battleship class Void shields.
Standard Main Armament: 8 Super Heavy 'Victus' Missile Batteries (2 batteries per broadside), 4 Heavy Plasma Lances (2 per broadside), 5 Heavy Lance turrets (dorsally mounted), 6 torpedo launchers
Standard secondary Armament: Turbo lasers, missile banks and autocannons (belly and spine mounted, undetermined numbers)
Auxiliary craft: 4 Arvus lighters, 1 Aquila lander, 1 tetrarch assault-lander, 2 Devourer drop ships, 12 Furies
Lore: The Vanquisher Class is a Unique vessel. The ship combines long range lance batteries with Macro Cannons in one broadside and has limited carrier capacity.
Only one Vanquisher is known to exist in the 41st Millennium, the Vae Victus, a Ship which was built at the special request of Lord High Admiral Javor in M32 at the shipyards of Hydraphur: although more ships of a similar layout to this Battleship are known to have been in service in small numbers during the Horus Heresy and Great Crusade, all are currently lost and believed to have been destroyed since or during the Horus Heresy.
Vae Victus herself appears like a highly modified Apocalypse Class Battleship at a first glance: have a broadside armament consisting largely of lances and dorsal lances, but the Vanquisher has little in common with the Apocalypse: having distinctly a different interior system layout and power plant, missile weapons and carrier capacity. She once had a larger series of Strike Craft launch tubes in the forward section of the ship and under the prow, an old and experimental precursor to the existing Ordnance launch bays, and a single battery of Lances and Macro Cannons together with Dorsal lances. Making her more like the Oberon Class Battleship. She has since been refitted to have her early hanger launch tubes replaced with specially made missile launchers and Prow Torpedoes, a small number of the strike craft launch tubes are still in action however and are used to launch scouts and small escorts of fighters.
The Vanquisher is typical in her armour layout, and the combination of many long-range lances and missile batteries makes her a deadly foe to any she came across, the carrier capability also making her not so vulnerable to Ordnance. Vae Victus served with Battlefleet Ultima in a similar role to the Retribution Class Battleship: Heavy Line Ship and Assault Battleship.
She left Active service with Battlefleet Ultima in M38, but is being re-activated for active service in M41.