The Garmatron is a massive tank with an oversized main cannon and Dark Matter ammunition, designed to upset the balance of light and darkness in the world.
The Garmatron is massive and powerful, able to crush or push aside anything in its path - despite this, it can also move fairly quickly for its size. Its armaments include movable spikes between its treads, and cylindrical turrets on either side of its hull that can fire regular energy blasts or Dark Matter rounds. Its primary weapon is the massive cannon on its front, which can fire projectiles clear across the Endless Ocean. Its usual ammunition is a large missile with a Dark Matter warhead, allowing it to infect large portions of land with pure evil energy. The cockpit—located at the top of the machine—features a lever-activated trapdoor in the middle of the floor, allowing the pilot to drop enemies into a shaft which shoots them through a door, and out through the back of the Garmatron. Likewise, the back of the machine displays two crossbows that act as as a lesser means of attack.
Although the Garmatron has not displayed any structural weaknesses, its weaponry has a few exploitable flaws. Its side turrets can be commandeered by enemies and turned against the Overlord's own forces. Additionally, its main cannon has a twenty-second warmup period before it can fire its first shot, and its Dark Matter ammunition must be loaded manually into a port on its side.
Following its transformation, the Garmatron was converted into a massive tower that easily dwarfed all of the other buildings in Ninjago. In this form, though immobile, the Garmatron retained its powerful armor, with its cannon being converted into a more compact turret that could quickly maneuver around its side, needing a rider to operate it. Though no longer firing Dark Matter, the turret was extremely powerful, with both the Ultra Dragon and Golden Mech failing to withstand even a single shot. Additionally, its shots were much more rapid in succession and didn't need to be manually loaded, making the machine's attacks far more difficult to evade. However, despite this, the turret became noticeably less armored, as an attack from Kai was eventually able to disable it.
During his battle with the First Spinjitzu Master, The Overlord created the Celestial Clock, with the intent that once it finished its countdown, it would activate, powering up the Garmatron. Before he could begin construction, however, the Overlord was defeated and the Stone Army was buried away, with the Island of Darkness and the Celestial Clock being sunk beneath the waves. Nevertheless, the Overlord, weakened, anticipated the day his champion, the prophesied Dark Lord, would arrive and construct the Garmatron.
- The Garmatron's hull resembles the Helmet of Shadows.