Realm of Madness

The Dark Realm (aka Lord Garmadon's Dimension) is one of the sixteen realms parallel to Ninjago, seen in LEGO Ninjago: Masters of Spinjitzu. It is described as a place where evil flourishes, due to an imbalance between the forces of light and darkness. The Mountain of Madness is located here, and the native inhabitants include Mud Monsters and Craglings.

Weapons of Destiny
Contrary to what he led the Skulkin to believe, Lord Garmadon's true goal during his time in the Underworld was to escape his prison, not wield the power of all four Golden Weapons. The reason for this became clear when Samukai claimed all of the Golden Weapons and attempted to use them against Garmadon - the combined power of the weapons was beyond anyone's ability to control.

As Samukai disintegrated into a portal, Garmadon explained to Sensei Wu and the Ninja that he intended to use the portal to reach a place where the forces of good and evil were unbalanced - there, he could gain the power he needed to wield all four Golden Weapons at once. After a final bitter exchange with his brother, Garmadon fled through the portal, which disappeared once he passed through.

Tick Tock
After Lloyd was kidnapped by the Serpentine, Sensei Wu decided to seek the aid of Lord Garmadon. Travelling to Mystake's tea shop in Ninjago City, he purchased some Traveler's Tea and used it to transport himself to Lord Garmadon's Dimension. Upon arrival in the dark realm, Sensei Wu was immediately confronted by Lord Garmadon himself, who had been mutated during his time in the dimension.

Once Bitten, Twice Shy
Now sporting new armor and an extra set of arms, Garmadon attacked his brother, forcing him into a mud pit with three Mud Monsters. Before the creatures could envelop him, Sensei Wu revealed Lloyd's plight, prompting Garmadon to save his brother and agree to a temporary alliance in order to save his son.

With that settled, the brothers set out for the Mountain of Madness, where Garmadon said they could find a portal that would return them to Ninjago. As they walked, Sensei Wu brought Garmadon up to speed on what was happening in Ninjago, prompting the four-armed villain to express regret that Lloyd had tried to follow in his evil footsteps.

The Royal Blacksmiths
After climbing the Mountain of Madness and fending off a Cragling attack, Wu and Garmadon finally reached the portal that would allow them to escape the dimension. At that moment, Garmadon pushed Wu into the portal, gloating that he had only agreed to the alliance so he could return to Ninjago and steal the Golden Weapons - thanks to his time in the dark realm, he could now wield all four at once. With that, Garmadon jumped into the portal himself, reappearing in Ninjago with his brother.

Day of The Great Devourer
After several adventures with the Ninja and his brother, Lord Garmadon went to Mystake's shop to order some Traveler's Tea, apparently intent on returning to his dimension after all. Before Mystake could fill the order, however, Garmadon had left the shop to aid the Ninja against the Great Devourer.

Kingdom Come
During Fenwick's explanation of the sixteen realms, one of the realms he showed the Ninja was the Dark Realm.

Curse World - Part II
The Dark Realm was one of the realms Morro and Lloyd went to during their fight over the Realm Crystal.

Appearances

 * LEGO Ninjago: Masters of Spinjitzu
 * "Tick Tock"
 * "Once Bitten, Twice Shy"
 * "The Royal Blacksmiths"
 * "Kingdom Come"
 * "Curse World - Part II"

Trivia

 * The Dark Realm has two methods of entry: Traveler's Tea, and the Realm Crystal.
 * It has three methods of exit: a consistent portal atop the Mountain of Madness, Traveler's Tea (if the traveler brought any), and the Realm Crystal.