The physical Omega figure has plain black minifigure legs and uses the same head and torso pieces as the other Oni figures from 853866. He also comes with a combination motorcycle helmet/Oni mask that is the same as the other Oni mask pieces from 70643 Temple of Resurrection, but in black and with unique printing. The horns that fit into this mask were originally introduced in 70795 Mask Maker vs. Skull Grinder. He is depicted with shoulder armor originally created for the Ninjago line in 2015, with a pair of black katana. He also comes with a black staff made from a black flagpole piece, a black tassel piece introduced in 2016, and a transparent purple stud.
In the animated series, the printing from the Omega's torso continues onto his legs, and he wears a black cape and carries no katanas. His staff is also more organic looking, resembling a gnarled tree branch similar in shape to Borg Tower. At its base is a purple crystal, resembling pieces originally created for the Belville line.
In March of the Oni, an illustration of the Omega is seen in one of Sensei Wu's books when he looks up the legend of the Oni. The Omega is later visible in the darkness enveloping Ninjago City, seen just before Cole is rescued by Lloyd and taken onto the Destiny's Bounty 3.0. When Lloyd and Emperor Garmadon arrive beneath Borg Tower to destroy the Realm Crystal, they are initially thwarted by the Omega's appearance. The Omega is puzzled by Garmadon's resistance, recognizing him as a fellow Oni, and by the fact that Garmadon hasn't already taken the realm of Ninjago himself. He reveals that the Oni intend to destroy the power of creation once and for all, and engages the two in battle.
Proving a formidable match for the pair and defying the powers of the Sword of Sanctuary, the Omega is nonetheless unable to stop Lloyd from destroying the crystal. However, the Oni have already opened their portal and no longer require the crystal, which the Omega demonstrates by summoning a horde of his minions. They pursue the pair through the Borg Tower vaults, but are temporarily repulsed by the Golden Master's armor. Despite this, the Oni follow the pair out into the city and swarm them, with only P.I.X.A.L.'s timely arrival in the Samurai X Mech saving the pair.
The Omega later leads his army to the Monastery of Spinjitzu, and is engaged in battle by Garmadon. Despite the emperor's assistance and the reforged Golden Weapons, the Omega and and his forces continue to advance, with the Omega taking out Cole's Earth Driller. When Garmadon takes his full Oni form to engage the Omega, the Omega notes that he has only the form of an Oni, and that his heart longs to be human. He is able to overpower Garmadon, and the Ninja and their allies are forced to retreat into the Monastery. However, when the Ninja, Wu, and Garmadon come together in a Tornado of Creation, the Oni-including the Omega-are overcome and vanish.
- The Omega's name is possibly meant to show his opposition to the Firstbourne, who leads the dragons as he leads the Oni.