Long, long ago, in the time before time, mata-nui, the great spirit, descended from the heavens, and brought peace to the lands. He unified the inhabitants of the islands, bio-mechanoids known as the matoran, into 6 groups. "Ko", the prefix in matoran language meaning "Ice", "Ta", the prefix in matoran language meaning "Fire", "Ga", the prefix in matoran language meaning "water (or in Metru-Nui's case, protodermis)", "Po", the prefix in matoran language meaning "rock/stone", "Onu", the prefix in matoran language meaning "earth", and "Le", the prefix in matoran language meaning "wind/air". The great spirit Mata-Nui also gave the matoran the 3 virtues:
Unity
Duty
Destiny.
The matoran honored the great spirit, and so the island "Mata-Nui" was named. But Mata-Nui had an evil brother, who was very jealous of these honors. So he came down to the island, and spread his darkness. He cast a powerful spell that put Mata-Nui to sleep, and he covered the island of Mata-Nui in darkness. He infected the creatures that lived there, such as the Nui-Rama, Nui-Jaga, Kofo-Jaga, Muaka, and Kane-Ra with infected masks. And masks were the power sources of the island.
Allow me to explain. Every living being on Mata-Nui had a mask. This mask was their source of power. There are several different types of masks. Basic masks, the kind that the matoran wear, are generally powerless and are worn as a kind of power-support. Without a mask, any being on Mata-Nui would eventually weaken. The matoran would sort of "shut down", and several rahi might as well. Normally, after an extended period of time without a kanohi mask, the toa or turaga or whatever is not wearing it will begin to weaken. A toa would never shut down, just be weakened. Anyways, toa masks, or "Great Kanohi", as all masks are called "kanohi", have great power, and this power depends on the shape. Noble kanohi are great kanohi, only weaker. Turaga, the village elders, wear the noble kanohi, but a toa could easily wield them as well. A matoran can only wear basic matoran masks. Turaga can only wear Noble Masks and basic masks, though there would be no point in wearing basic masks. A toa can use Great, Noble, and basic, though it would seem much more logical to use the Great masks, as they are easily the most powerful. Here is a list of the masks, who wears them, and their powers:
[Hau-toa tahu (red): shielding]
[Miru-toa lewa (green): levitation]
[Kaukau-toa gali (blue): under-water breathing]
[Akaku-toa kopaka (white): X-ray vision]
[Kakama-toa pohatu (brown): extreme speed]
[Pakari-toa onua (black): immense strength]
[Huna-turaga vakama (red): invisibility]
[Mahiki-turaga matau (green): illusion/shapeshifting]
[Matatu-turaga nuju (white): telekinesis]
[Rau-turaga nokama (blue): translation.]
[Komau-turaga onewa (brown): mind-control]
[Ruru-turaga whenua (black): night-vision and X-ray vision]
[Kiril-turaga dume (metru-nui, no actual element or color): regeneration]
[Avohkii-toa takanuva (mask of light, no village): turn anger to peace, freeze opponents in a column of light]
[Kraahkan-makuta (great spirit-evil) spread darkness, fill a hero's heart with darkness, fear, and anger]
[Vahi-nobody (this mask was created by vakama when he was still a mask maker. Makuta had requested it under the diguise of turaga dume. the only two ever to wear it were toa tahu nuva when the bohrok kal threaten to re-unleash the bohrok, see storyline, and toa vakama {see movie spoilers})]
Special Kanohi: [Infected Masks- worn by the beasts of Mata-Nui when Makuta infected them, also worn by toa lewa for a short time when he was captured]
[Copper Masks- given out as prizes to the winners of tournaments, no actual power. Makuta destroyed them all in an attempt to crush the morale of the matoran.]
Storyline:
After Makuta defeated Mata-Nui, he infected the island beasts and tried to destroy the matoran. There were many fierce battles and much of the beauty of Mata-Nui had been destroyed. The charred jungle was all that was left of the once active jungle by Ta-Koro. (Note: all villages end with the suffix koro. i.e. Ta-Koro, Le-Koro, Onu-Koro, etc. The outskirts of the villages are called wahi, i.e. Ta-Wahi, Po-Wahi, Ga-Wahi, etc.) Later, when the matoran could hold back the rahi no longer, an adventurous matoran named Takua summoned the 6 toa with the power of the toa stones.
The warriors arrived on the beaches of the island in canisters, and after a while, the canisters exploded, and the pieces of the toa flew out. Slowly, the toa started to build themselves, then they went to their villages. After being told everything they needed to know by the turaga, they were off on their quest for the masks. 30 powerful Great Masks had been hidden all over the island of Mata-Nui, 5 for each toa to collect. They needed the powers of these masks to challenge Makuta. According to an ancient prophecy, after each toa had all 6 of their great masks, (each toa had to have a set of 6: hau, kaukau, miru, akaku, pakari, kakama) they would place them in the ancient shrine of kini-nui and be gifted with the ultimate mask; a gold one. The gold mask had the powers of all 6 combined, only it was stronger. They would need the gold masks to defeat the dark spirit known as Makuta. This journey would be called the "Quest for the Masks". Of course, the masks were hidden all over the island, and they were guarded by the beasts, called rahi. The toa had to defeat the rahi, collect the masks, and journey to Kini-Nui.
And after winning many battles, the 6 toa journeyed to the heart of the island, Kini-Nui. There they placed all 6 of their masks, and a gold mask came out. After they put on the gold masks, they were ready to challenge Makuta. But Makuta was a Great Spirit. He would not be easily defeated. He had many rahi to fight for him, and the deadly Manas, the most powerful of rahi, to guard his lair.
The toa journeyed deep down into the island, and met the Manas. Finding the Manas much smarter, tougher, and stronger than the other rahi, the 6 toa combined, creating the two toa kaita. Toa kaita Wairuha, the toa kaita of wisdom, is created from Lewa, Gali, and Kopaka, and wears the kanohi Rua, the silver miru of wisdom. Toa kaita Akamai, the toa kaita of valor, is created by Onua, Tahu, and Pohatu, and wears the kanohi Aki, the gold mask of valor.
Together they journeyed deep into Makuta's underground lair and challenged the Manas, which were large, powerful rahi. But the Manas were more than a match for them. After all, the Manas had much strength in numbers. When the kaita were on the verge of defeat, Toa Kaita Wairuha discovered that the Manas were mechanical, and that destroying the control towers would take the Manas out of action. And so they met Makuta, and found him... A tohunga.
An infected tohunga wearing an infected mask. Looking at the surprise on their faces, Makuta said, "Am I not what you were expecting? Well then, were you expecting THIS?" And with that, Makuta joined with the floating pieces behind him. Suddenly cables flew everywhere, grabbing the toa. The toa shook off the cables, and united, used their elemental energies to blast Makuta. After the goliath of jumbled parts and pieces had fallen, Makuta said, "You cannot defeat me. For I am nothing." And with that, the toa were beamed back to the surface.
The chronicler Takua, who had seen all this, went into the next cave through a giant door in the wall. There, he saw many strage shaped pods. He looked inside. A bohrok looked back.