Created alongside the rest of their brethren by the Overlord, the Stone Warriors were tasked with destroying the First Spinjitzu Master to bring an era of darkness. Initially speaking many different dialects, this diversity would be quelled when Kozu, desiring a homogenous, common language for efficient communication, threw the Stone Warriors who spoke difficult dialects down the Mount of Eternal Shadows.
With efficient communication amongst the army and the command of Kozu and the Overlord, the Stone Army was led successfully against their foe. However, the Stone Warriors would be defeated when the First Spinjitzu Master split Ninjago in two, before proceeding to capture and entomb every warrior left in Ninjago in the Stone Army Tomb. With their master gone and trapped, the Stone Warriors eventually went dormant.
Stumbled upon by the Serpentine beneath Ninjago City, the dormant Stone Warriors were initially mocked and derided as mere statues until the venom of the Great Devourer, dislodged by the constant digging of the Constrictai, seeped into the tomb and infected the statues. Reawakened by the dark influence, the Stone Warriors promptly attacked the Serpentine, eventually defeating their intruders after initial conflict and leaving them trapped in their tomb. Freed, the Stone Warriors proceeded to wreak havoc, destroying a portion of Ninjago City before attempting to attack the survivors, likewise cornering Wu and Misako. However, their attempts would be foiled after the Ninja rescued everyone in the Destiny's Bounty and fled.
Needing Dark Matter to power the Garmatron, Garmadon set the Stone Warriors to work harvesting the corruptive essence from the island. After spotting the Falcon spying on them, a single Stone Warrior succeeded in downing it with a boomerang and bringing it back to Garmadon's camp.
Harvesting several troves of Dark Matter, at the cost of losing multiple Stone Warriors in the Mouth of Eternal Shadows, the Stone Warriors continued their work. However, upon noticing Zane attempting to rescue the examined Falcon, the Stone Warriors chased after them in pursuit, with several being thrown into a pool of Dark Matter in the process. Pursuing the fleeing protagonists alongside Kozu, they eventually scaled up the mountain to the Temple of Light. Despite their best efforts, the Stone Warriors were unable to prevent Lloyd from unlocking the Golden Power and the acquisition of the Elemental Blades, and unable to withstand the onslaught, were forced to retreat.
With their attention diverted into creating more Warrior Bikes and other vehicles of destruction, the Stone Warriors were quickly herded back into completing the Garmatron at the Overlord's command. After noticing the Ninja disguised as them, the Warriors pursued the fleeing protagonists, who'd taken the Helmet of Shadows in the skirmish. Although initially losing them in the chase, the Stone Warriors eventually caught up, arriving at the downed Garmadon's aid and saving him from the Ninja. Confronting their enemies at the Celestial Clock, the Stone Warriors succeeded in delaying the heroes long enough to finish the countdown and activate the Horns of Destruction, and triumphant seized Nya and escaped.
With all Warriors regrouping under Garmadon's command, the Stone Warriors marched out to the Island of Darkness coast behind the completed Garmatron, fighting back the Ninja and ensuring the Dark Matter missiles infected parts of Ninjago. With their master strengthened by the growing evil, the dark entity possessed Garmadon and led the Stone Warriors into battle. Despite their attempts, however, they were overwhelmed by the power of the Ninja, and the Overlord, deciding the fight inconsequential, transported his forces to Ninjago City.
Seizing the capital once more, the Stone Warriors set up a defense around the Garmatron, now transformed into a massive fortress. Meeting initial opposition by Lloyd in his Golden Mech, the Stone Warriors quickly took advantage of the machine's destruction to circle the Green Ninja and his allies. However, Dareth, finding the Helmet of Shadows, donned it and unknowingly seized control of the Stone Warriors. Now under his command, the Stone Warriors marched up the Garmatron, only to be knocked off Nya's turret and kept back. After the Overlord was destroyed in an explosion of light, the Stone Army vanished, becoming no more and being sent to the Departed Realm.
Requiring others to distract the Ninja from his plans, Yang tricked Cole into using the Yin Blade to catalyze and open an exit from the Departed Realm to Ninjago, releasing the souls of a few Stone Warriors, who promptly inhabited statues modeled after them in the Ninjago Museum of History. Regrouping under the command of their similarly-resurrected general Kozu, the Stone Warriors attacked Dareth in vengeance over being controlled and chased him back into the museum. Their efforts would be for naught, however, with Dareth rediscovering the Helmet of Shadows and using it to take control. Now in command once more, Dareth proceeded to order the Stone Warriors to kill Kozu by repeatedly slamming him into a wall, an action with which they performed without hesitation.
Saving Faith (Flashback)
When Wu was regaining memories from his youth to being lost in Time, one memory showed Wu and Misako in a building from the episode, "The Day Ninjago Stood Still", with the Stone Army behind them.