Digital Overlord

The Digital Overlord (also known as the Overlord Virus) was The Overlord spirits' digital form. Following the final battle between him and Lloyd, the Overlord took on the form of a computer virus, residing at Borg Tower which was built upon where the Garmatron tower once stood. The Overlord corrupted Cyrus Borg into a robotic maniac, using him as a vessel to carry out his plans, including seizing control of Borg Industries' vehicles and deploying the Nindroid MechDragon after Lloyd.

A mysterious figure, later revealed to be Pythor, would take the Overlord to his secret underground lair. Pythor aided the Overlord in tracking down Lloyd, whose Golden Power they hoped to steal in order to transform the Overlord into the Golden Master. Pythor would eventually capture Lloyd and he would soon be drained of his element.

The Overlord confronted the Ninja as they entered the Digiverse. Despite having the upper hand, the Overlord was overwhelmed as the Ninja used the Golden Power and erased him from the Digiverse. Despite this, the Overlord's spirit would survive and he would go on to become the Golden Master.

Pre-Season 3
Following his final battle with Lloyd, the Overlord was seemingly destroyed. However, the ultimate evil managed to endure or reform himself after his defeat, apparently lying dormant in the crater left by the destruction of the Garmatron fortress. When Borg Tower was built over the crater, the Overlord somehow converted himself into a digital form that infected the Borg Industries network.

The Surge
The Digital Overlord seized control of Cyrus shortly after he left the Ninja with a moving statuette of himself. When the statuette was shattered, revealing the Techno Blades, the Digital Overlord took control of Borg Tower's security systems and attempted to claim the powerful weapons for himself.

The Art of the Silent Fist
Following the Ninja's escape from Borg Tower, the Digital Overlord tortures Cyrus Borg, transforming him into the "OverBorg." While P.I.X.A.L was erasing the raw golden power from all of the technology built for the city, the Digital Overlord lamented the loss of his body before commanding P.I.X.A.L to search for the Golden Ninja, dismissing her protests of being programmed for the Techno Blades. Following this, the Digital Overlord commanded Cyrus' new Nindroid army to scan throughout the city for the Ninja, region by region.

When Master Wu refuses to reveal Lloyd's whereabouts, the OverBorg uses a laser to scan through the old Master's mind. The Digital Overlord was confident that Master Wu would crack, but was unnerved by his constant laughter. Later, the Digital Overlord deploys the MechDragon, to pursue and capture the Gold Ninja.

When Min-Droid accidentally destroyed the only power generator in New Ninjago City, the Digital Overlord was deactivated. However, the evil entity remained in a dormant state - only by hacking Borg Industries' mainframe with the Techno Blades would the Ninja be able to destroy their foe once and for all.

Blackout
The hard drive containing the Digital Overlord's main consciousness was stolen from Borg Tower by a mysterious hooded stranger. After being reactivated, the Digital Overlord allied with the stranger in order to complete his mission: finding Lloyd and taking his golden power for his own. He was pleased to discover that the Stranger could reactivate the Nindroids by using Electrocobrai as personal power sources. The villains also tracked Lloyd and his father to a forest and began preparing to capture them.

The Curse of the Golden Master
The Digital Overlord possessed one of his Nindroid minions to confront the ninja in the Serpentine's tomb. He was knocked back into stasis after his host's Electrocobrai was removed, but he later managed to take over the Nindroid MechDragon. With his new body, the Digital Overlord teamed up with the stranger—soon revealed to be Pythor—to capture Lloyd and knock Garmadon into the ocean.

Enter the Digiverse
After capturing Lloyd in the MechDragon, the Digital Overlord began absorbing his golden power, hoping to become the Golden Master and take over all of Ninjago. When he learned of the Ninja's attempt to erase him through the Digiverse, he sent Pythor, General Cryptor, the Nindroids, and Techno Wu in a full-scale attack on Borg Tower to attack the Ninja's physical bodies—and to ensure their demise, he confronted them personally within the Digiverse. The Digital Overlord attempted to stop the Ninja's consciousnesses by turning the Digiverse upside down, trapping them in quicksand, and even summoning the Digital Kraken, but the heroes prevailed and seemingly destroyed the villain with their combined powers.

Codename: Arcturus
Unbeknownst to the Ninja, the Digital Overlord endured his defeat, having drained enough of Lloyd's golden power to regain physical form. However, when his allies extracted him from the deactivated MechDragon, he was revealed to be a shapeless blob of dark matter (likely due to the power drain being interrupted). With Pythor concealing his new form to avoid disturbing the Nindroids, the Digital Overlord began scheming to launch the Arcturus rocket into space, in hopes of reclaiming the lost Golden Weapons.

Ninjago: Decoded
A remnant of the Overlord Virus' code (Trapped in a Memory Loop) was found in Zane, and slowly began corrupting him in order to take control of his body and exact his revenge on the Ninja. But by using good memories, they managed to erase the rest of the Overlord Virus, for good.

Season 3: Rebooted

 * 27. "The Surge"
 * 28. "The Art of the Silent Fist"
 * 29. "Blackout"
 * 30. "The Curse of the Golden Master"
 * 31. "Enter the Digiverse"

Trivia

 * It is unknown how The Overlord converted himself into a virus, but considering his role as source of all darkness in Ninjago, he may have simply recovered after his defeat, taking his digital form to adapt to the increased technological progress of New Ninjago City. It is also implied that Cyrus's construction of Borg Tower over the remains of the Garmatron may have reawakened the remnants of the Overlord's being, which merged with Borg's technology to regain his strength.
 * The Digital Overlord can transfer himself into any Nindroid technology at will.
 * The Digital Overlord planned to become the Golden Master by draining Lloyd's golden power to use to materialize his own body.

Gallery
Ultra-Böses