The Underworld helmet was Garmadon's first helmet and a symbol of authority in the Underworld. It previously belonged to Samukai. When Garmadon put on the Helmet of Shadows, he left this helmet behind next to the Celestial Clock.
Long before the pilot episodes
Once fallen warriors began to populate the Underworld as undead Skulkin, the helmet was put to use as a symbol of authority amongst the skeletons, with Samukai eventually arriving and seizing it for his own.
An Underworldly Takeover (flashback)
With Garmadon banished to the Underworld, the disgraced hero sought a means of escaping the realm by taking control of the Skulkin, and after defeating a vengeful Samukai in combat, donned the helmet for his own.
With the symbol of Skulkin authority now his, Garmadon would proceed to command the skeletal beings, wearing it even after betraying and forsaking the fallen warriors.
- In the design phase, Kruncha's minifigure wore a helmet that looked identical to the original version of this helmet.
- In the sets, the helmet comes in two forms; The first in the 2011 sets, being comprised of the traditional Samurai helmet with the small bone piece, and later the 2012 (and Legacy) version, with the helmet now replaced by the new, narrower helmet used on Samurai X.
- It is unknown what happened to the helmet after Garmadon discarded it, though it was likely left on the Dark Island.
- There are a few errors involving the switch between the helmets.
- Garmadon did not appear to remove his original helmet before donning the Helmet of Shadows in "The Day Ninjago Stood Still," and the original helmet is nowhere to be seen in the following moments.
- In "The Last Voyage," when Garmadon was coming down to see the Stone Warriors and the Dark Matter, he was wearing his original helmet, even though he should have been wearing the Helmet of Shadows by then.
- One of the evil samurai in "The Mask of Deception" and "Big Trouble, Little Ninjago" (both released in 2018) wears a helmet identical to the original version of this helmet despite the part being retired since 2011.
- While not appearing in Master of the Mountain aside from the Ninjago history mural, the helmets the Re-Awakened wore bear a striking resemblance to this helmet, though the helmet and bone were colored black.
- In the graphic novel, Night of the Nindroids, Lloyd jokingly calls the helmet a "bone hat".
The images on Underworld helmet need to be organized.