It's known regions were Ru-Koro (Underground/Earth), Tapa-wahi (Tropical/Water), Maunga-wahi (Snowy Mountains), Aera-nui (Forest/Ruins), Hu-koro (Light Jungle), Nei-koro (Dense Jungle), Ki-koro (Desert), Mo-koro (Water/Ice), Ahi-koro (Volcanic/Fire), Mata-koro (Castle), The Crystal City, and Rao-wahi (Desert/Stone).
The plot was similar to the official one the everyone knows. Mua Nui was a Great Spirit (or was believed to be by the Matoran). Aera was a jealous female who imprisoned Mua Nui and turned all the Matoran into monstrous beings called Raok. Here is the official write-up for the story:
All of Mata-Nui was underground to see Makuta defeated, his merging with Takanuva temporarily, and finally, the opening of Mata-Nui’s chamber. But what awaited all of Mata-Nui was not the god of the island, it was a city. The “City Of Legends”. The place that everybody would learn of their destiny-but some weren’t destined to go to this city. Many dropped down onto the island as a large group stood by and watched, but before they too could leave-the chamber started to collapse, and the portal to the island was closed when the roof of the chamber collapsed onto it. Not thinking another second-the group ran. But the many tunnels beneath the Kini-Nui are misleading, and everybody was led to a dead end. Well, almost…
What they found was beyond imagination. Another portal, but they could not see what lied on the other side, all they could see what a cloudless, blue sky. Would they risk appearing in a world of nightmares, or should they turn back into the fast collapsing cave and risk being crushed? There was no time for questioning, and everybody quickly jumped through the portal…
What lied on the other side was an island of mystery. Uninhabited towns scatter the island with only remnants of a race far more advanced than Mata-Nui’s. What happened to the people that were here? And more so, is anybody else here? What do the walls of unusual writings that scatter the island tell a story of? Things have changed, and things aren’t black and white any more. There are now so many greys in between.
As our heroes plummet from the portal in the sky they just came out of, we can only imagine-what does this island hold in store for them? Find out when destiny ends, on this island of Mua-Nui.
Their purpose is unknown. Why they attack anything is unknown. What they are is unknown. The Raok are mysterious beasts that appeared out of nowhere on Mua-Nui. Each one stronger than Makuta himself, and what more-they appear in swarms. The Raok are not an easy foe to defeat, even by the most skilled warrior. What more, the Raok are intelligent-moving on their own free will unlike the Rahkshi or Bohrok, making them a foe to be reckoned with.
Powers: Mist, Cloaking, Invisibility
This white Raok can make himself invisible. Kraok can create a mist so nobody sees anything anymore, cloak himself and others or turn himself into mist/clouds. If he changes himself into mist/clouds he cant be harmed by physical attacks but he can still attack. Kraok is not very good at attacking, but IS very good at defending. He is quiet, not aggressive, hides himself most of the times and always walks at the back of a group of Raok.
Powers: Infections, Virus Control
He can infect enemy's, give them viruses, and make them weaker. Oraok can infect enemy's over short distances with his staff or by touching an enemy. This gives him a big advantage, because if someone touches Oraok even a little, that character will be poisoned.
Powers: Spikes, Knifes
This brown Raok can shoot spikes and knife like objects out of his body. From his hands, legs, chest, back, etc. Praok likes to torture enemy's. He can transform his limbs into sharp objects. He is the most aggressive Raok.
Powers: Weather Control, Flying
She controls weather. Graok can create tornado's, storms, heavy winds, thunder and more. Graok is very aggressive for a female creature. She also has the ability to fly.
The main role of Traok is spying. He can change into any form but will not get all the powers of this form. If he changes to Makuta, he will not be able to do strong dark attacks. If Traok changes to Tahu Nuva, he just looks like Tahu. He does not like to fight a lot, for he has no elemental powers. Traok lets the other Raok kidnap or kill someone and he then changes into that character to take over their roll, learn secrets and tell them to his peers.
Powers: Plants, Roots, Nature
He can control the plants. Leraok can make plants grow or dissolve them. He can create aggressive, biting plants, poisonous plants, and all different kinds of organic material. Leraok can also pull enemy's under the ground with roots. He is not very aggressive. Leraok usually hides in the bushes and strikes when the enemy is not expecting an attack.
Nothing much is known about Aera, besides the fact that she is a powerful sorceress holding Mua-Nui, the god of the island, captive. Aera is female, and very powerful. She puts the powers of Fear, Anger and Fire to good use. Nobody could come face to face with Aera and survive for long. Though she is rumored to have one giant weakness far under the ground...
Below is the event post that transported us to our next region: Metru Nui.
Aera sat in her throne in the crystal city. Her Raok minions were yet to make any true advances on the new "inhabitants" on her island. It was unbelieveable, the nerve of the fools.
Having the souls of the ex-matoran encased in her crystal, re-creating new Raok using the souls was not a difficult matter. But with her new plans, she would destroy these trespassers before they even knew she existed. In the past.
7 shadowed creatures-her minions-stood ready before her. She sighed, she had hoped it wouldn't come to this, that the trespassers would just bow down before her, but-as it was always with ignorant fools-they insisted on going down in a flurry of death. So be it, she thought to herself, and her new minions would seal their deaths.
Aera stood up, and the 7 minions before her bowed immediately. Aera opened her mouth to speak when she noticed a figure appear in the corner of her eye. Looking over, Aera spotted her prisoner, walking free of her crystal prision.
"Mua-Nui!" Aera yelled, pointing at the figure that just appeared. "How did you get out?"
"What matters, Aera, is that I am out. And I am going to stop you now before you can do anything later."
"Oh, I wouldn't worry about that." Aera looked over at her 7 minions and pointed at a blue portal in the corner of the room. "I've already done something."
The seven minions reacted immediately and ran for the portal. Mua-nui swung her head towards the portal and yelled out a short "No!" as Aera's minions jumped through, the portal closing in a small flash of light behind them.
Mua-Nui spun back to Aera and growled. "Do you know what you have just done? All of time itself could be changed!" Aera growled back. "Stop me"
"I plan on it."
Meanwhile, all over Mua-Nui, the "trespassers" start disappearing...