Toa Mata

The Toa's history is shrouded in mystery. Series writer Greg Farshtey holds the opinion that they actually started their lives as Toa, unlike most Toa who were transformed as Matoran - however, he points out that while he writes the storyline with this assumption, it is not a definite fact. At the very least, they are among the oldest existing Toa, being over 90,000 years old, created with the purpose of aiding the Great Spirit Mata Nui in case the worst happened to him.

Origins
Sadly, the worst did happen; Makuta had attacked Mata Nui with such force that he eventually fell unconscious, bringing on the Great Cataclysm. In response, the Toa "descended from the heavens" in Toa canisters that landed in the sea (though Turaga Dume has suggested that the Toa didn't come from the heavens, but were launched into the sky from somewhere on land). The intention was that they would land on the island of Mata Nui, where refugees from the city of Metru Nui had escaped, and begin their task of awakening the Great Spirit. However, the canisters malfunctioned and floated in the ocean for centuries, causing their organic parts to decompose while only their mechanical parts remained.

Introduction to Mata Nui
A thousand years later, a Matoran on Mata Nui named Takua collected the six Toa Stones and brought them to the Kini-Nui Temple, located at the center of the island. The Toa Stones shot a beam of light into the air that carried Takua and smashed him on the beach below, erasing his memory. The canisters carrying Tahu, Toa of Fire, Gali, Toa of Water, Lewa, Toa of Air, Onua, Toa of Earth, Pohatu, Toa of Stone, and Kopaka, Toa of Ice finally began to make their way to the island. When they arrived, the Toa found the island in the grip of Makuta, as it had been for exactly nine hundred ninety nine years (Makuta had spared the island for a year) who had enslaved the Rahi wildlife to do his bidding with Kraata-infected masks. Over time, the Toa's biological components regenerated as they set out to stop Makuta and free the Matoran, collecting Kanohi Masks to add to their abilities. Once they each collected a full set of masks, they were each given a Golden Kanohi and a Makoki Stone; they used the Makoki Stones to unlock the path to Makuta's underground lair, Mangaia. There, the Toa faced Makuta's guardians, the Manas crabs and the Shadow Toa, before facing the Master of Shadows himself.

The Toa Mata vs the Bohrok
However, Makuta was only using a fraction of his power. Taking the appearance of an infected Matoran, he transformed himself to a mass of flying pieces and fought the Toa. After deciding that they were indeed the heroes that they said they were, he retreated with the words "You cannot beat me, for I am Nothing". But he would not allow the Toa to rest: he awakened the Bohrok, swarms of insectoid creatures whose mission was to reduce the island to bare rock - a normally harmless species, but when awakened too early would definitely seem harmful. The Toa had to act fast to save the Matoran villages, but not all succeeded: Onu-Koro was completely flooded, Po-Koro also had to be evacuated, and almost all of the Le-Matoran - including Lewa - was assimilated into the swarm through the Bohrok's mind-controlling Krana. However, the Toa would continue to fight and collect the Krana that could unlock the swarm's secret - Onua and the Onu-Matoran were even able to help free Lewa and the Le-Matoran from the swarm's influence.

Kopaka was eventually able to find the Bohrok's nest, and once the Toa were gathered they entered to stop the swarms once and for all. In the cave for a brief period of time, Tahu went ahead of the group into a chamber filled with Tahnok, where he was briefly controlled by a krana. After Tahu made the room explode and gained his mask back, the six Toa descended into the heart of the nest. Coming across a series of niches, the Toa placed the Krana they collected inside them. This unlocked six doors, behind each of which was a powerful suit of armor called an Exo-Toa. After suiting up, the Toa went in to face the Bohrok Queens, Cahdok and Gahdok. But despite the extra strength that the armor granted, the Toa still struggled; they eventually figured that the Exo-Toa were blocking their elemental powers. They removed the armor and combined their elemental powers into a single blast, which imprisoned Cahdok and Gahdok in a protodermis cage. The Toa had won, but before they could celebrate, the floor gave way beneath them and they fell into energized protodermis, a substance that either transformed or destroyed what it came into contact with, depending on its destiny. The Toa were destined to transform, and they became Toa Nuva; with stronger powers, new tools, and enhanced masks.