The Sons of Garmadon were a crooked biker gang pledged with resurrecting Garmadon with more than 300 members. The group was originally led by Princess Harumi, a.k.a. "The Quiet One," and sought to conquer Ninjago and resurrect Lord Garmadon—who Harumi viewed as Ninjago's savior (because he destroyed the Great Devourer). To bring about his rebirth, the group searched for the three Oni Masks and revived Garmadon at the Temple of Resurrection, though they were arrested when the ceremony seemingly failed.

The reborn Garmadon freed Harumi along with the rest of the group, and the group took control of Kryptarium Prison. There, Garmadon fought and nearly killed his son, while the Sons planned to return to Ninjago City and showcase their new emperor - Garmadon. As Garmadon's Colossus terrorized Ninjago, it seemingly killed Wu and the original ninja. As a result, Lloyd created a Resistance to oppose Garmadon's rule, as his forces occupied Ninjago.

The Resistance fought the Sons of Garmadon, holding up against them for some time. During the conflict, Garmadon destroyed Mr. E after he failed to capture Lloyd, and Harumi died after the building on which she stood collapsed. During a climactic battle against Garmadon and the Colossus, Garmadon lost his element and the Colossus crumbled apart. As a result, most, if not all of the Sons were arrested and sent back to Kryptarium Prison.

Six months after the Oni's invasion, when the ninja were trying to find something to do, they inspected Killow's cell. After the ninja traveled to the Never-Realm, Ultra Violet made an escape attempt, along with the Mechanic and Fugi-Dove. However, they were arrested by Samurai X.