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Terminal.png This article, Leonidas-class Heavy Battleship, was written by Spartan-091. Please do not edit this fiction without the writer's permission.

Leonidas-Class Battleship.png
Leonidas-class Heavy Battleship
Production Information

Ares Shipyards and Fleet Systems, Inc.




I (2520 - 2568)
II (2570 - Present)


Heavy Battleship (BBH)

Technical Specifications

1503.6 meters (4,933 feet)


122.5 meters (401 feet)


235.6 meters (772 feet)


20,000,000 metric tons

Maximum Acceleration

5000 miles/second

Maximum Speed (Space)

10,000 miles/hr

Maximum Speed (Air)

500 miles/hr

  • 3 Ares Fleet Systems MMX0982 "Mauler" Fusion Drives
  • 65 Chemical Micro-Positioning Thrusters
Slipspace Drive

Shaw-Fujikawa XP335-XL FTL Drive

Slipspace Velocity

12 light-years/ day

  • Cougar Dual-Core Fusion Reactor
  • Cougar Sunfire Backup Solar-Power Generator



243.84 centimeters (8.0 ft) Titanium-A Battleplate

Sensor Systems
  • Aegis Mk. V Deluxe Sensor Suite
  • Aegis RR93 Radiation Dosimeters
  • Aegis "Hawkeye" Long-Range Spectro-Analysis System
Targeting Systems

Aegis "Panoptes" Mark III Target-Acquisition Systems

Navigation System

Columbus Astrogation Computer

  • 4 Heavy Magnetic Accelerator Cannons,
  • 88 Archer Missile Pods
  • 3 SHIVA nuclear warheads
  • 2 Longsword Squadrons (24 Longswords)
  • 1 Broadsword Flight (4 Broadswords)
  • 2 Pelican Squadrons (24 Pelicans)
  • 1 Albatross Flight (3 Albatrosses)
  • 1 Orbital Drop Shock Trooper Company
    • 41-67 Troopers
  • 32 Human Entry Vehicle launch tubes
    • 64 Human Entry Vehicles
  • 2 Marine Corps Companies
    • 180-400 Marines

1075 Navy Personnel

Skeleton Crew

125 Crewmen

Service Information
First Introduced




Operational Role

Carrier Battlegroup Defense, Planetary Protection

In Service With

UEG Seal.png Unified Earth Government
UNSCDF Shield.gif United Nations Space Command Defense Force Navy


"The Leonidas line of ships was designed with the intent of actually standing up to Covenant craft on a one-on-one basis. It sports one of the largest arsenals in the fleet, has the third-thickest hull, and is, all things considered, a wonder of a craft; as for fleet roles: it's surprisingly versatile for such a giant."
―CEO Julio Gavin, Ares Shipyards and Fleet Systems, Presentation of Concept to the Admiralty: January 2520

"One big son of a bitch, that's for sure. Dunno how the hell they got enough power to run the damn thing, but we're always trying to squeeze the last bit out and into the systems when we engage..."
―ET1 Junko "Scotty" Shintani

The Leonidas-class battleship is one of the leading classes of heavy warships in the UNSC Navy. It is deployed with carrier battlegroups and planetary siege task forces, as its heavy weapons and relatively low speed make it perfect for long- or close- range fleet defense roles. Only a few of these ships were produced before the Human-Covenant War, and most were destroyed in the heavy fighting for the Inner Colonies that took place during the later stages of the conflict. After the Human-Covenant War, Ares Shipyards and Fleet Systems, Inc. announced that they were in the process of designing a second, more cost-effective model of the Leonidas line, allowing the UNSC to field more of these powerful craft. High Command was delighted, and quickly signed an order for eight of the newer models. ASFS, Inc. engineers are currently finishing the first ship of Block III.


Leonidas-class ships are basically giant weapons mounts, with a lesser amount of room for stores, shore party Marines, and strike craft. The superstructure is built around the 4 Heavy MACs that are the primary weapons, with a large magazine of the cannons' metallic projectiles attached to the "bottom" of the ship. Kinetic suppressors take up a lot of the battleship's 1.5 kilometer length as well. The bridge is located in the middle of the dorsal superstructure, with a clear view of the ship's trajectory. To the rear of the bridge are the crew quarters, a small strike craft/planetary support craft hangar, and supply bays. Sensors are dotted all over the superstructure, to provide a clear view of the ship's position in space.

The three large fusion engines at the stern of the design, which are supported by another engineering section, have back splash suppressors built onto them to prevent the accidental destruction of support craft who wander into their wake. At the extreme fore of the ship, on the dorsal superstructure, is a weapons-control bridge, where spotters and weapons-specialists ensure that each MAC shot is on target and accurately place. The rest of the fore area is an engineering section, with a small cryogenics bay to the rear of that section. Vehicles are housed near the strike- and planetary support craft hangar, in their own easily accessed bay.



At one and a half kilometers long, the Leonidas-class is one of the largest and heaviest designs used within the UNSC Navy, falling short of only the supercarriers in its length, width, and mass. Most of the interior space is used by the four Heavy Magnetic Accelerator Cannons, with the remaining modules taken up by crew quarters, marine barracks, hangars, along with supply and vehicle bays. The battleship is known for its cramped quarters and lack of major cargo space, but it is also feared because of its multi-role capability; since it carries a wing of Pelicans and about two companies of marines, it is quite adaptable.


The three large fusion engines of the Leonidas design are manufactured and installed directly by Ares Shipyards and Fleet Systems itself, designed specifically for heavy ships like the battleship, carrier, or Super Carrier. They are mostly used to bring the ship up to a considerable rate of drift, or for drastic combat maneuvers. The rest of the ship's movement is handled by the large array of chemical-based thrusters, which are positioned evenly about the superstructure. A concerted firing of these thrusters can move or position the ship relatively quickly, adjusting its drift with short micro-bursts.

The most impressive part of the Leonidas-class, apart from its primary weapons, is the Shaw-Fujikawa XP335-XL Slipspace drive, which is, amazingly, capable of generating a hole into Slipspace big enough for the battleship to pass through. Also astounding is the rate at which this massive craft of able to travel within Slipspace: somewhere around 1 light year every two hours!


The Leonidas-class is capable of generating power in two different ways: by its dual-core fusion reactor and by its backup solar-power processing system. The fusion reactor is one of the best of its time, providing the necessarily large amount of power for the weapons, engines, and life support systems within the battleship. If the reactor is somehow forced to shut down, the emergency solar panels can provide minimum power for a short period of time while the reactor is fixed. Because of the weak nature of solar power processing, only one MAC can be fired while the ship is on emergency power, as the rest of the more vital ship's systems take up the majority of the solar energy. Captains of Leonidas-class vessels quickly learned to increase the amount of power taken in by their ships solar panel arrays, rotating the ship so that the arrays face the star of the solar system. In deep space, however, where there are few nearby stars, the battleship is in serious trouble if the fusion reactor fails. Thus, these ships are usually only deployed in defense of solar systems or fleets operating in solar systems.


The battleship's superstructure is entirely made up of A-Grade Titanium Battleplate, as is standard for UNSC ships. The reflective coat of the armor, which is relatively new, gives the class more protection from directed energy weapons than earlier battleplates, but is still rather weak when compared to Covenant anti-energy armor, as it can only dissipate one plasma bolt before beginning to melt. The armor's main strength is its ability to repel most ballistic projectiles without any permanent damage. In fact, the Titanium Battleplate can absorb two direct hits by MAC rounds before beginning to collapse, an astonishing tribute to the ingenuity of UNSC engineers.


This is where the Leonidas-class truly lives up to its moniker of "heavy battleship". It has an impressive arsenal which includes 4 Heavy MACs, numerous Archer missile launchers, and several tactical nuclear warheads. These weapons allow Leonidas vessels to be true protectors of the fleet, prepared to engage the enemy at long, medium, or close range.

Heavy Magnetic Accelerator Cannons

The Heavy MAC is a standard MAC which has been upgraded to fire heavier projectiles at even greater velocities than before. At present, the best HMACs can fire a 1 kiloton round at speeds of up to 4,000,000 feet per second. One round is enough to significantly damage or even eliminate the standard shielding of smaller Covenant warships. An interesting feature of the Leonidas-class is that it is able to fire all four of its HMACs simultaneously in a four-rounds-at-once "haymaker", as it has been affectionately dubbed by crewmen. This "haymaker" is capable of destroying a ship such as a Covenant frigate in only one firing. The only significant weakness in this tactic is that the firing of all four HMACs greatly drains the power reserves of the vessel, disabling all other weapons systems for a period of fifteen to twenty minutes or longer. So, while the "one-shot-one-kill" theory is superb as a company bragging line, it is rarely attempted, and is even discouraged by UNSC High Command .

Archer Missile Pods

The Leonidas-class, like all other ships in the UNSC fleet, is equipped with a significant number of Archer Missile Pods, proportionate to its size and classification. The heavy battleship boasts an impressive 88 pods, each with 25 missiles. These chemically-propelled warheads are quite powerful, and are used against ship of Human design, or against Covenant ships that have lost their shields. Archers are, by nature, long-range missiles, designed with a built in auto-arm time, which allows the missile to clear friendly lines before becoming dangerous. The weakness in this is that the missiles are unable to be used at distances shorter than a kilometer, and thus completely ineffectual in anti-fighter defense. Close-range fighting is left up to the battleship's array of point-defense autocannons, which can quickly chew up incoming strike craft.

SHIVA Nuclear Warheads

The SHIVAs onboard the Heavy Battleship are meant to be used only for last-ditch, emergency situations, but smart C.O.s have used them to their full potential, taking out multiple Covenant craft with these warheads' heavy 20-megaton yield of radiation and destruction. In a pinch, the SHIVAs can be used for orbital bombardment as well, but this is strongly discouraged by High Command as the negative public relations effects of nuclear-bombing an overrun Human colony are immense.


To better its role as a fleet protector, the Leonidas-class was given a small-crafts hangar which stores a wing of Pelican troop transports, a wing of Longsword space interceptors, a flight of Albatross heavy dropships, and a flight of Broadsword space bombers. Also included in this storage area are numerous ground vehicles and the battleship's own cadre of single-person exterior repairs vessels. A battalion of marines is usually stationed onboard, living in the ship's cramped crew quarters and marine barracks areas. It is also not uncommon to find a platoon of Orbital Drop Shock Troopers (ODSTs) supplementing the garrison of marines; these soldiers provide the battleship with the ability to support Special Operations missions and bolster the garrison with their elite training.

Ground-Support Craft

  • D77H-TCI Pelican Dropship (24)- This ubiquitous dropship type is used to facilitate easy transfer of platoon-sized units of troops from the battleship to anywhere on a planet's surface, or to provide aerial support to units pinned down in the field. The squadrons usually stationed onboard Leonidas-class ships are easily able to move an entire company into the field at one time.
  • C709 Longsword-class Interceptor (24)- The Longsword interceptor, while primarily thought of as a space fighter, is actually capable of fulfilling several different tactical roles, including that of atmospheric fighter-bomber. The Longswords are usually deployed in support of larger UNSC forces on the ground, and are most commonly utilized in air superiority engagements, where Pelican dropships are an ineffective option.
  • D76H-CCH Albatross Heavy Dropship (3)- Albatross dropships are used mainly for transporting extremely heavy or cumbersome loads, such as multiple Scorpion MBTs, Warthog LRVs, or large amounts of ammunition to a planet's surface. It is rarely seen in combat, and is extremely vulnerable to enemy anti-aircraft units. As it is also rather bulky, Leonidas-class ships are only given three such transports, to save on space in the hangar bay.

Space Strike Craft

  • C709 Longsword-class Interceptor (24)- The Longsword interceptor, while primarily thought of as a space fighter, is actually capable of fulfilling several different tactical roles, including that of atmospheric fighter-bomber. The Longswords are usually deployed in support of UNSC forces in space, and are most commonly utilized in combat fighter superiority engagements, where Broadsword strike bombers are less effective.
  • C189 Broadsword-Class Bomber (4)- The Broadsword tactical strike bomber, which is a new type of space strike craft that was developed by Ares Fleet Systems in 2520, is used in a anti-support-craft role, taking out fleet tender ships and incoming trade craft. This allows a Leonidas heavy battleship to better enforce an embargo against an enemy planet or to disrupt valuable trade routes.


  • M12 Warthog LRV (50)- The vehicle of choice for UNSC Marines, the Warthog LRV is perfect for fast and stealthy reconnaissance of enemy terrain, and for quick evasion of enemy personnel. With the chaingun attachment, it also poses a significant threat to both unarmored infantry and any aircraft in the area.
  • M808B Scorpion MBT (25)- The main battle tank for the Marines, the Scorpion provides hard-hitting infantry and anti-tank support with its large main cannon and smaller anti-personnel machine gun turret. The backbone of any UNSC armored assault, the Scorpion has proved its effectiveness in countering the majority of Covenant vehicles.
  • M274 Mongoose ULATV (100)- A quick-response all-terrain vehicle that is employed by Force Recon Marines to get to forward observation posts in a shorter amount of time than the Warthog. More maneuverable and better in situations where a lower profile is required. Capable of carrying one passenger.
  • M831 Razorback TT (25)- The perfect transport for a squad of marines, this Warthog variant's extended troop transport compartment is capable of housing four extra passengers, a welcome change from the cramped quarters of the standard M12.


  • Navy Crewmen (1000)- The standard naval ratings responsible for the ship's day-to-day operations, along with a few specialists such as the weapons system crew, engineering crew, cryo bay operations staff, and pilots.
  • Navy Officers (75)- The officers who are in direct control of the ship's systems, or in charge of a certain area on the ship. Most of these men and women are on the command or weapons bridges at all times, with the exception of the engineering and cryo officers.
  • Marines (400)- The troops and officers that make up the ship's "shore party", or ground effect complement. All ground assaults are left up to the men and women who serve in this branch. Includes soldiers, medics, combat engineers, support crews, and heavy weapons teams.
  • ODSTs (67)- The most specialized infantry that the UNSC has, ODSTs make orbital insertions in Human Entry Vehicles that are stored near the hangar bay. They are responsible for protecting the captain of the ship in case of enemy boarders or forced landing, and for any special operations that need to be conducted.

Model II Upgrade

The Leonidas Model II hull upgrade added significant features to the ship when it was authorized in the late 26th century. Using technology proven by the UNSC Infinity on its maiden voyage and subsequent effectiveness in the Requiem campaign, the upgrade focused primarily on bringing the ship's defensive systems up to par. As such, it added a shipwide shielding unit, upgraded the armor plating with the new Forerunner-derived material used on the Infinity, and generally improved electronic and multi-spectrum countermeasure systems, promoting survivability that was previously absent against directed energy weapons.

Ships In Class

Block I

(Original Proof of Concept: 5 Ships)

  • UNSC Leonidas (BBH-101)- Self-destructed in the Battle of Reach, obliterating several Covenant cruisers as well.
  • UNSC Menelaus (BBH-102)- Destroyed in the Battle of Reach.
  • UNSC Odysseus (BBH-103)- Active, veteran of several actions against the Covenant
  • UNSC Myrmidon (BBH-104)- Damaged in Manheim Campaign, repaired and still active.
  • UNSC Agamemnnon (BBH-105)- Destroyed engaging the Covenant at Harvest while in Admiral Cole's fleet.

Block II

(Refitted and Updated Hulls to Leonidas Model II: 2 Ships)

Block III

(Full Production of Model II: 6 Ships)

  • UNSC Diomedes (BBH-106)
  • UNSC Patroclus (BBH-107)
  • UNSC Achilles (BBH-108)
  • UNSC Nestor (BBH-109)
  • UNSC Ajax (BBH-110)
  • UNSC Spartan (BBH-111)

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