Thunder Spears are rocket-propelled explosive weapons developed by the Survey Corps specifically to counter the Armored Titan's impenetrable armor. These shoulder-launched projectiles consist of a metal spear tip packed with high explosives, propelled by a small rocket motor toward the target. The weapon was conceived by Hange Zoe after the Survey Corps failed repeatedly to penetrate Reiner Braun's armored hide using standard Ultrahard Steel Blades during the battle for Wall Rose. Thunder Spears feature a two-stage detonation mechanism designed to pierce armor: the initial impact drives the spear into the target's surface, followed by a delayed explosion that maximizes internal damage. They represent the first Paradis-made weapon specifically engineered to kill Titan shifters rather than normal Titans.
Thunder Spears are designed to be launched from modified ODM gear mounts, allowing soldiers to fire them while in motion and at range against armored targets. The weapon is most famously used in the Return to Shiganshina arc, where Levi's squad employs a coordinated Thunder Spear assault against the Armored Titan. Each spear is approximately one meter in length with a stabilizing fin assembly at the rear, and soldiers typically carry two to four spears per mission. The explosive payload is powerful enough to blow through the Armored Titan's hardened skin and even break his armor plates with concentrated volleys. After their success against the Armored Titan, Thunder Spears were produced in larger quantities and used against other Titan shifters, including a devastating point-blank shot that killed the Cart Titan's user during the final battle.
Thunder Spears are primarily used by Survey Corps veteran soldiers who have the combat experience and tactical awareness to deploy them effectively against Titan shifters. Levi Ackerman became the most devastating Thunder Spear user, employing them in conjunction with his ODM gear to execute the massacre of Zeke Yeager's Beast Titan forces in the forest. The weapons require specialized training to use safely, as the rocket backblast and delayed explosion can injure the user if fired too close to obstacles or allies. During the Jaegerist coup, Thunder Spears were manufactured in large quantities and deployed by both the Survey Corps loyalists and the Jaegerist forces, leading to devastating anti-personnel use of these weapons in the harbor battle that resulted in the destruction of Paradis's newly constructed fleet.