|Former Residents||The Piraka|
The Piraka Stronghold was a massive fortress built on Voya Nui by the local Matoran who had been enslaved by the Piraka who had came to their home in search for the Kanohi Ignika, the Legendary Mask of Life. The Piraka had been sent to Voya Nui by Makuta Teridax to recover the Mask of Life for him. To gain the initial trust of the Matoran, the Piraka pretended to be Toa. This tricked most of the Matoran, but some were skeptical. The Piraka enslaved the Matoran by using Zamor Spheres tainted with Teridax's Antidermis. Only the Piraka leader, Zaktan knew that the substance was Teridax's essence and only six of the Voya Nui Matoran evaded capture.
When the Stronghold was complete, no Matoran were allowed inside the structure unless they were ordered to by the Piraka. Inside the stronghold there was a chamber which held a crystal vat which contained Teridax as Antidermis. From this, the Piraka took minute amounts of Teridax's substance and tainted their Zamor Spheres with it to corrupt the Matoran to follow their every order. Inside was also the Chamber of Truth, and robots known as Nektann who guarded the stronghold.
The Toa Nuva came to Voya Nui to also claim the Ignika, but to revive Mata Nui. The Piraka defeated them and then ordered the Matoran they had corrupted to throw the Nuva's weapons and masks in the nearby volcano, Mount Valmai. But before this could be done the volcano erupted earlier than first thought, and the Toa Inika came and saved them and their weapons and masks. The Inika then fought and defeated the Piraka. It is presumed that the Piraka Stronghold was destroyed when Voya Nui crashed back into the Matoran Universe through Mata Nui's chest and smashed into Mahri Nui.
- The Piraka Stronghold was released in the summer of 2006 as a playset. It had a set number of 8894.
- The Piraka Stronghold set was the largest and most expensive set released in 2006, and was the only set to include mini-figures of all six Piraka and Toa Inika.
| Fire Regions: Mt. Valmai • Lake of Lava • Chamber of Life • Lava Reservoirs|
Water Regions: The Cape of No Hope • Lagoon Entrance • Mahri Nui (Formerly) • Voya Nui Bay
Village Regions: Matoran Stronghold • Matoran Village • The Jungle Sanctuary • Canyon Fortress
Piraka Regions: Piraka Stronghold • The Chamber of Truth • Piraka Outpost
Ignika Chambers: Staircase to the Ignika • The Zone of Nightmares • The Chamber of Death • Umbra and Protodax's Chamber • Lava Chamber Gate
Other Regions: Ring of Ice • Cavern of Historical Records • Desert of Sorrows • The Green Belt
Lake of Protodermis • Nui Caves • Stone Cord (Destroyed)