The royal helmet of Onaga the Dragon King
This ancient royal helmet with two long horns (the Dragon King's Helmet or sometimes known as the Crown of the Dragon King or Crown of Onaga) is the most prized possession of Onaga the Dragon King, the legendary emperor of Outworld. The helmet was shown not worn and fallen after the player defeated Onaga and he exploded in the arcade mode of Mortal Kombat: Deception where it made its debut appearance. It was also featured as one of the collectible Relics under the name "Onaga's Helmet" in the Konquest mode of Mortal Kombat: Armageddon.
Onaga the Dragon King still forever wears his beloved crown (Onaga's Helmet)
Long before Shao Kahn's rule in Outworld, this helmet forever served as Onaga's crown as the Dragon King was the true and rightful ruler of Outworld that was once a majestic empire and and unified realm. After being ousted, it now serves as a helmet used in battle.
Some say this helmet helps protect the Dragon King's only known weak spot.