As he watches over the city from his new throne on Borg Tower, Harumi reported to Garmadon that Lloyd still hadn't been caught and he was confused by Lloyd's defiance to him since Lloyd had nothing while he had everything. Garmadon was posed to use the Colossus to destroy half the city to draw him out but Harumi stopped him as that action was unnecessary.
Harumi suggested sending Mr. E who is more than capable to find and procure Lloyd, accepting of the latter's talents, Garmadon orders him to find his son.
Lord Garmadon requests Harumi, Mr. E, Ultra Violet, and Killow's presence at the top of his palace in the Borg Tower. The soulless Garmadon demands to know who failed to capture his son. They all secretly tremble in fear, until Mr. E steps forward. Despite Harumi's protests to defend him, Garmadon still kills Mr. E and threatens Harumi and her remaining generals that he will tear them apart next if they fail to capture his son again.
Lord Garmadon summons Harumi again to the top of his palace; when she fearfully approaches him, he tells her that his son is near. Although Harumi assures him that Lloyd would be a fool to come anywhere near Borg Tower, she quickly withdraws her statement when Garmadon angrily asks her if she thinks he is a fool. She then assures him that she will take care of security. When Garmadon wanders Borg Tower looking for Lloyd, he is about to see past Skylor's efforts to camouflage the group, until Harumi arrives from the elevator, asking Garmadon if he is okay. He tells her that he believes Lloyd and the others are on the next floor, ordering Harumi to follow him. This slip in judgment gives Lloyd and company the time needed to break in the broadcast room and encourage the public to rise up against their self-proclaimed Emperor. Lloyd also challenges his father, forcing Garmadon to angrily growl at the top of the tower as he watches the broadcast.
Lord Garmadon requests Harumi, Killow, and Ultra Violet's presence at the top of the Borg Tower. Harumi willingly but fearfully admits that she failed to stop Lloyd's broadcast, and Garmadon agrees. Ultra Violet accuses Harumi of letting it happen, after which Garmadon prepares to tear her apart with Destruction, although Harumi begs him to spare her since she brought him back from the dead. Garmadon then retorts that he has no heart and no mercy, and he is about to kill Harumi until she reveals that she knows the location of the Resistance's base. He ultimately spares her, and upon learning the base is in the garbage depot, then sends a Sons of Garmadon battalion to the base.
After Lord Garmadon's forces captured most of the Resistance, the dark lord appeared on a roof and used his Destructive Powers to control the Colossus, having it chase after Lloyd, Nya, Skylor, and Dareth. When the Colossus had cornered them, he attempted to crush their vehicle with them inside of it. After sensing Lloyd begging him to stop, Garmadon momentarily hesitated, but then continued.
However, P.I.X.A.L. used this distraction to shoot him with her samurai armor, breaking his focus and control over Colossus, allowing Lloyd, Nya, Skylor, and Dareth to escape. The enraged Garmadon then shot her out of the sky with a Destructive Blast allowing Killow to capture her. Garmadon could only stare in disappointment as his son escaped the city.
After, the raid on the Resistance's HQ, Garmadon's forces sent the captured Elemental Masters and their supporters to Kryptarium Prison.
After this successful ambush, Garmadon seemed to disappear, confusing the likes of Killow and Ultra Violet. When Harumi finds him, he is confused by his hesitation to crush Lloyd. He is struggling with his lingering affection for his son, having believed only the darkness and brutality of his Oni side were brought back. Harumi corrects him, stating that "a child isn't born from a side, a child encompasses all." Meaning that Lloyd came from all parts of him, including his Oni side, and thus his love for Lloyd still existed.
Harumi attempts to convince him to cast aside Lloyd as his son, in order to escape what holds him back and fully unlock his True Potential, and embrace her as his daughter. Garmadon reveals to Harumi that his true reasoning behind seeking strength and conquering Ninjago, was to defeat an "endless night" he saw during his time in the Departed Realm, which struck fear into him and threatens his "father's realm."
After his revelation, the dark lord accepts Harumi as his new daughter, the princess promising to do whatever it takes to help her "father" defeat this evil.
Mistaké, disguised as Harumi, comes before Lord Garmadon with the "captured" Skylor. Unknown to Garmadon, Harumi was captured by his son and the Resistance plans to have Skylor absorb Garmadon's power in order to control his Colossus. Just as Garmadon approaches Skylor, Ultra Violet warns him that "Harumi" forgot to add that Skylor is the Master of Absorption. Garmadon then becomes suspicious, although Mistaké, still disguised as Harumi attempts to talk her way out of the situation when the real Harumi and Killow arrive at the top of Garmadon's Palace in the Borg Tower.
Upon seeing two Harumis, Garmadon lets the newly-arrived one to speak in order to deduct who the real Harumi is. After learning the first "Harumi" is Mistaké in disguise, he congratulates the real Harumi for her efforts. Garmadon then convinces Mistaké to show her true Oni form, and a fight commences between them. He is losing for most of the fight, until Mistaké uses her powers to make a smoke screen around them, giving Skylor the opportunity to absorb his Destruction power. With Mistaké now powerless after making the smoke screen, Garmadon kills her off-screen.
Lloyd, Nya and Dareth help Skylor as she attempts to take control of the Colossus using Garmadon's element. Realizing his creation is being hiijacked, Garmadon regains control of it, but Skylor attempts to regain control. The two struggle for possession of the Colossus; during the chaos, Harumi flees the roof of Borg Tower and runs into a nearby apartment building. After helping a family escape, she tries fleeing the building, but the Colossus crashes into it—causing the apartment to collapse. Garmadon is devastated by the loss, which only stokes his rage further, as he now intends to raze the city in pursuit of Lloyd.
As a result of Harumi's death, Garmadon is fueled with rage and begins to destroy the city with the Colossus.
Garmadon senses his brother's return, realizing that he is still alive. He also sees the Ninja are still alive too and sends the Colossus to destroy them while Wu and Lloyd continue onto his palace.
From the shadows, Garmadon greets his family and declares them as enemies, Garmadon battles Wu and Lloyd before knocking Wu out of the battle and facing only Lloyd. Garmadon continues to attack Lloyd—and nearly knocks him from the tower twice—but saves him every time. Lloyd then attempts to convince his father to change back to how he used to be, but Garmadon proclaims that people don't change, they only reveal who they truly are.
After hitting the Dragonbone Blade out of Lloyd's hand, and watching it fall down to the city, Garmadon screams at Lloyd to get up and fight him. When Lloyd refuses, Garmadon angrily continues to attack him, but Lloyd uses his father's own technique to resist him. Because Garmadon gets his power from fighting, when Lloyd refused to fight him, his Destruction power got progressively weaker until it completely faded away. Now defeated, Garmadon orders Lloyd to finish him off, and when Lloyd refuses to deliver the final blow Garmadon then warns his son that "they are coming."
Lloyd then brings his defeated father down to the streets where he is swarmed by many police officers before he is arrested. Garmadon pleads to Lloyd to believe him by rambling that "they" will come before being taken to Kryptarium Prison along with the Sons of Garmadon.