|This Titan's power allows its user to create weapons and more from inside the ground by controlling Titan hardening.|
|— Eren Yeager assesses the power of the War Hammer Titan|
The War Hammer Titan (戦槌の巨人 Sentsui no Kyojin?) is one of the Nine Titans with the ability to create structures out of hardened Titan flesh. Until the year 854, it was kept within the Tybur family for generations. It is currently in the possession of Eren Yeager.
The War Hammer Titan can produce and manipulate structures that are made up of hardened Titan flesh. The structures can be weaponized—forming pikes large enough to impale and lift a Titan, flood areas with protrusions such as spikes, and manifest its signature war hammer. This ability can also create flexible weapons, such as the string of a crossbow or the whips of a cat-o'-nine-tails out of its own brand of hardening.
Much like the Female Titan, this hardening can also be used to encase the human operator of the War Hammer in a crystal. While durable, this crystal can be damaged when struck or crushed by a more resilient structure, such as the Jaw Titan's claws and teeth.
Unlike any other Titan, it is possible for the War Hammer Titan to remove its control center from its nape. If this is the case, the body of the Titan will be connected to its human operator by a long cable of flesh. If the cable is severed, the War Hammer Titan will be rendered inactive, although a new body can still be made. Unlike the rest of the Nine Titans, the Titan body can emerge from the ground upon transformation because its operator does not need to be inside of its nape.
This ability, when combined with the hardening abilities, makes the War Hammer Titan incredibly difficult to defeat: the Titan itself has no weak spots and the human operator is protected inside an extremely durable crystal.
The War Hammer Titan, like all the Nine Titans, was brought into the world after the death of Ymir Fritz. In the 1,700 years following her death, the War Hammer Titan was held in the possession of one or several of the warring Eldian houses subservient to the Founding Titan. After these seventeen centuries when King Karl Fritz abandoned the conflicts of Eldia and relocated to Paradis Island, the War Hammer Titan had come into the possession of the Tybur family. At some point, the uprising peoples of Marley took part in the Great Titan War, and the Tybur family were the first Eldians to come to their aid in the early days of the war.
After the Great Titan War, the War Hammer Titan remained in the possession of the Tybur family, who swore to defend the new nation of Marley as honorary Marleyan aristocrats. However, despite their vow, the War Hammer Titan remained unused in battle throughout the next century. For reasons of security, the identity of the War Hammer Titan within the Tybur family was kept a secret from all but a select few high-standing individuals in Marley.
After the Marley Mid-East War, Zeke Yeager develops some concerns towards the fate of the Eldian race given the world's rising technological advantage over the Titans and, by extension, over Marley. In order to improve the reputation of the Eldians in the eyes of other nations, Zeke convinces the Tybur family to support the next attack on Paradis Island with the power of their War Hammer Titan.
Shortly afterward when the Tybur family arrives in Liberio, Willy Tybur converses with Commander Theo Magath concerning the state of their nation. When asked whether Magath can determine which Tybur holds the War Hammer Titan, Magath admits he is at a loss. However, Magath later notes that Willy speaks of the history of his family and nation as if he had witnessed it firsthand. Willy admits that he has indeed seen history firsthand due to the memories that the War Hammer Titan has carried throughout its inheritors within the Tybur family throughout the past century.
After Willy is killed and eaten during the festival play by Eren Yeager as the Attack Titan, his younger sister transforms into the War Hammer Titan; however, the Attack Titan interrupts the transformation and punches the War Hammer in the face—the beginning of an onslaught. Eventually, the War Hammer Titan recovers and generates spikes in the ground that immobilize the Attack Titan. The War Hammer Titan regenerates its upper body and completes the transformation, and creates an enormous war hammer for itself to use. Trapped, and being shot at by anti-Titan artillery, the Attack Titan is unable to successfully block the incoming swing of the War Hammer Titan's hammer and is swiftly beheaded. After decapitating the Attack Titan, Eren emerges from its neck, and the War Hammer Titan prepares to deliver the killing blow. As it asks for his final words, Eren calls for Mikasa Ackerman who suddenly appears from behind and catches the War Hammer by surprise. Despite trying to stop her, a barrage of Thunder Spears is launched by Mikasa and land at the back of the Titan's neck, setting off a massive explosion that sends it crashing to the ground.
The War Hammer Titan stands back up and forms a smaller pike, launching it at Eren and Mikasa. Avoiding it, Mikasa re-engages the War Hammer Titan while Eren, seeing that the inheritor was not located in the nape, tries to track where the inheritor is hiding and notices a long cable stemming from the left heel of the Titan. Following it and transforming into the Attack Titan once more, Eren finds the younger sister of Willy underground and attached to the end of the cable encased within a crystal.
The Attack Titan proceeds to sever the cable, rendering the War Hammer Titan immobile, and then attempts to eat the inheritor; however, the Jaw Titan comes from behind and ambushes the Attack Titan. The ensuing skirmish buys the younger sister of Willy enough time to reform the cable and generate a new War Hammer Titan body, trapping the Attack Titan in a web of Titan substance.
However, the Attack Titan instinctively hardens its arm to protect its nape from the attack. The Attack Titan attempts to devour the War Hammer Titan once again, but fails due to the crystal barrier shielding the operator. Realizing the War Hammer Titan is out of power, Eren frees himself from the nape of the Attack Titan, and transforms once more.
Picking up the crystal in his new body, the Jaw Titan rushes to attack Eren. The Jaw Titan unleashes a fury of attacks with its sharp claws, leaving a deep scratch on the crystal when Eren raises it to protect himself. Later, when Galliard tries to attack the Survey Corps' airship, Eren and Mikasa dismember his Titan. The Attack Titan jams the crystal into Galliard's mouth and forces him to crush it. Eren has her fluids drain into his Titan's mouth, gaining the power of the War Hammer Titan.
While he is imprisoned, Eren explains to Hange that he ate the War Hammer and can easily use that Titan's abilities to leave his prison whenever he wants, no matter how tough and deep the underground cell is.
- On February 8th, 2018, Hajime Isayama revealed on his blog a rough draft of the War Hammer Titan's head and neck.