The Marleyan military (マーレ軍 Māre-gun?, also translated as Marleyan army) is the combined armed forces of Marley, consisting primarily of the Marley army (マーレ陸軍 Māre Rikugun?) and the Marley navy (マーレ海軍 Māre Kaigun?). Their main strength comes from the infamous Warriors, who have the power of the Titans.
According to Yelena, in the year 851, the Marleyan army boosted a total strength of one million men organized into 50 divisions of 20,000 strong. The navy had a total of 21 battleships among three fleets as well as an unknown amount of destroyers. However, it is unclear whether these numbers still hold true after the Marley Mid-East War given that Marley has suffered heavy casualties in that war with over half their naval fleet being destroyed by the Mid-East Alliance.
Chain of Command
The various branches of the military are collectively led by a general, formerly General Calvi before his death, then succeeded by General Theo Magath. Below the general are commanders who are responsible for the control and training of a combat unit.
Marley practices conscription in the conquered lands of its empire, although its own citizens are presently exempted from military service. Due to that, its rank and file is made up of various ethnicities, with the Eldian unit being the most visible among them.
The Marleyan army (マーレ陸軍 Māre Rikugun?) possesses a conventional armament that is largely similar to other world powers in appearance, but is noted to be more obsolete. For small-arms weaponry, bolt action rifles and stick grenades are the standard-issued weapons of Marleyan infantrymen, with two models of rifle in service. War Chief Zeke Jaeger also carries a sub-machine gun into battle, suggesting that automatic small-arms are used at least by Marley's elite Airborne Unit. Heavier weapons such as water-cooling machine guns are employed as the primary armament of the Cart Titan in particular, turning them into mobile weapon platforms manned by Marleyan soldiers known as the Panzer Unit (パンツァー隊 Pantsā-tai?). Soldiers are primarily transported by steam-powered trains, but those who garrison inside home territory are also transported by trucks.
In 852, the army consists of 50 divisions, comprised of 20,000 soldiers each, for a total of 1,000,000 soldiers.
The use of Titans is central to the army's doctrine. Besides having the Warriors as a strategical deterrent, Marley also has a long-standing strategy of converting its Eldian population into pure Titans to bolster its military strength. In ancient times, pure Titans were set loose by the Eldian Empire an enemy force en masse, as they are unable to follow complex commands except from the Founding Titan. Marley's tactic remains much unchanged from Eldia's in the modern era, except that the Titans can now be airdropped by airships.
Other than strategic value, inheritors of the Nine Titans also fulfill the tactical role comparable to tanks on the field. For example, Porco Galliard was tasked to destroy a machine gun nest which was otherwise untouchable by infantry in the battle against Fort Slava. A more literal example is Pieck, who possesses four machine guns turrets strapped to the armor on her Titan's back, a configuration that proved highly effective in clearing the Allies' trench system. Otherwise, Marleyan troops practice conventional tactics such as trench warfare, frontal human wave assault, and rudimentary anti-armor techniques such as the use of bundle stick grenades.
However, due to their heavy reliance on the power of the Titans, the Marleyan army has neglected development and advancement of conventional armaments. As a result, its forces were gradually outclassed by the Mid-East Allied Forces and other nations of the world, who pushed their efforts into military development in order to strike a balance with Marley's Titans. 
The army has little regard for proper conducts of war. For example, Magath intentionally allowed Warrior candidate Gabi Braun to attack an enemy pillbox in plainclothes, even though he was aware that this would be a violation of international law if anyone remained alive to report it.
- Main article: Panzer Unit (Anime)
Heavier weapons such as water-cooling machine guns are employed as the primary armament of the Cart Titan in particular, turning them into mobile weapon platforms manned by Marleyan soldiers known as the Panzer Unit (パンツァー隊 Pantsā-tai?).
One of the forces in the Marleyan army is the Eldian Unit (エルディア人部隊 Erudia-jin Butai?). The army's hierarchy is ethnically segregated, with Eldians forming the entirety of the enlisted ranks led by an all-Marleyan leadership. As a clear indication of rank, Eldian soldiers are issued with headgear differing from their Marleyan superiors, and all are required to wear the nine-pointed star insignia identifying them as Eldians at all time unless when being explicitly ordered to take it off. The Eldians soldiers have a color signifying their rank, grey is Eldian soldier, yellow is Warrior candidate, and red is Warrior. Like in civilian society, Marleyan officers are generally disdainful of their Eldian subordinates, but some are less so. For example, Commander Magath is more willing to communicate with his Warrior candidates, and even allows them opportunities to celebrate, although those were likely done out of pragmatism. On the other hand, his subordinate Marleyan officer Koslow is openly contemptuous of the Eldians, and he seeks every chance to belittle them. Despite the discrimination, Eldian veterans are entitled to medical care if they are permanently crippled or psychologically damaged in war.
- Main article: Warriors (Anime)
Before the year 830, Marley possessed seven Titans which assured its position as a world power. However, advancements in technology have started to undermine the military importance of Titans. Recognizing this fact, the Marleyan government planned to conquer Paradis Island to exploit its rich fossil fuel resources in order to improve their conventional military. The plan was hindered by Karl Fritz's threat of unleashing the Colossal Titans upon the world in case of a Marleyan invasion, though this threat was little more than a means of temporary deterrence.
In order to counter King Fritz's ultimatum, the Marleyan government decided to grant the power of the seven Titans in their nation's possession to a selection of children who are Subjects of Ymir, thus forming the Warriors (戦士 Senshi?). The families of those chosen children were promised to be made into honorary Marleyans with all freedoms that come with the distinction. These children were trained into expendable soldiers in warfare while also serving as candidates to inherit the powers of the Titans.
Over a dozen years later, in the year 845, Marley sent out four of their Warriors, Bertholdt Hoover, Reiner Braun, Annie Leonhart, and Marcel Galliard from their hometown of Liberio. These Warriors were given the task of breaching the gates of the Walls in order to wipe out the Eldians and take the Founding Titan from the royal family.
They succeed in breaching Wall Maria, though their efforts in breaching Wall Rose are halted upon learning that Eren Jaeger possesses the power of the Titans, leading them to suspect that he could have the Founding Titan they seek. Since that revelation, the goal of the surviving Warriors has been to capture Eren Jaeger in order to obtain the Founding Titan. However, after their failure at the Battle of Shiganshina District, the Paradis Island Operation has since been postponed due to the loss of the Colossal and Female Titans.
In the year 854, a group of candidates consisting of Gabi, Falco, Colt, Zofia, and Udo join the Eldian soldiers to help capture Fort Slava under the command of Theo Magath during the Marley Mid-East War. The same battle also sees Reiner, and Zeke being deployed on the field alongside a barrage of mindless Titan. Reiner is severely injured when he shields Zeke from a direct hit of a naval artillery shell.
The Warriors are now facing the threat of being outclassed by advanced technology in weaponry used by other nations against them. During the Raid on Liberio, the Scout Regiment matches the Warriors in battle, and even manages to overwhelm them when Porco Galliard breaks formation and leaves his comrades exposed. The forces of Paradis Island then manage to steal the War Hammer Titan from Marley and inflict some serious damage to the Armored, Jaw and Cart Titans while also successfully rally the Beast Titan to their side.
The Marley navy (マーレ海軍 Māre Kaigun?) is outdated and underdeveloped, which leads to devastating losses against the state-of-the-art naval warships deployed by the Allies during the Marley Mid-East War. During the war, it only manages to control the sea at the cost of half of its fleet after four years of fighting.
Marley has a variety of different warships in its navy, such as battleships, destroyers, ironclads, survey ships or steamboats.
In 852, the Marleyan Navy had a total of 21 battleships among three fleets. Despite poorer performance, the battleships operated by Marley after the war bear few differences to its Alliance counterparts in appearance, which may suggest that the ships were seized from the defeated Alliance as war compensation. The ships are steam-powered, fully steel built vessels, armed with two twin-gun main batteries of large-caliber naval guns as well as numerous smaller guns around the hull; pre-dreadnoughts.
The navy sent 32 ships including a number of destroyers to the coast of Paradis Island in the course of three years after the Battle of Shiganshina District. The purpose was to survey the area for the invasion of the island. All ships were lost to the Scout Regiment and a group of Marleyan dissidents - Consecutively, the latter group lured them in by sending out a fake distress call, allowing the Attack Titan or the Colossal Titan to ambush the vessels. Most members of the ship crews were captured. Over time, the survivors' hostility became smoothed out. Some would even cooperate with the Scout Regiment and become technical specialists.
During the fighting in Liberio, Magath gives orders to the navy, citing that the normal chain of command has broken down. This suggests that the head of the Marleyan navy was present for the Liberio festival and perished.
During the course of the battle, a Marleyan naval fleet arrives at a port near Liberio, in order to reinforce the Marleyan position. However, Armin Arlelt is waiting for them and proceeds to transform into his Colossal Titan form, obliterating the fleet and the port where the ships are docking.
The Airborne Unit (空挺部隊 Kūtei Butai?) uses airships to carry Eldians who are parachuted over a target area and transformed by Zeke's scream into pure Titans, who upon transforming lose their parachutes and fall violently on the enemy's territory, the kinetic force destroying much of the bombarded zone. Although a large percentage of the Titans die due to the fall, the remaining ones then proceed to decimate the surviving enemy forces. Members of the Nine Titans serving Marley such as the Armored and Beast Titans can then be parachuted as well, although from a lower altitude, to continue with the attack.
Marley Public Security
- Main article: Marley Public Security (Anime)
The Marley Public Security is a Marleyan internal military force. Its primary purpose is to control the Eldian minority within the Marleyan mainland. The MPS repression of Eldians drove Grisha Jaeger into becoming an Restorationist and led to the creation of several Titans which ravaged the Walled society in Paradis Island.
- The Marleyan military is often translated in English as "Marleyan army," but this is not to be confused with the ground division which is also translated as the "army." The Japanese terms are different, with the latter including the kanji 陸 riku, meaning "land."
- The Marley army's equipment seems like a mix of WW1 German and British gears. For example, Marleyan servicemen wear a headgear that shaped like Stahlhelm, while Eldian soldiers wear what appear to be Pith helmet. Furthermore, the Marleyan service rifle heavily resembles a Mauser Gewehr 98 rifle. In episode 63, Reiner attempts to commit suicide with a Gewehr 88 Commission Rifle, suggesting both weapons were used in Marleyan service. Strangely, the former rifle was used in Reiner's childhood while the latter rifle was used as a training weapon in the present day, even though the Gewehr 98 was a more advanced rifle in real life. At one point, Zeke is depicted using an m1 carbine.
- The Marleyan naval uniform at sea is nearly identical to its army counterpart, save for the addition of a life jacket. However, naval personnel stationed closer to home are dressed in blue sailor suits.