Great Cataclysm

The Great Cataclysm is a major event in the Bionicle history.

History
Sometime in the distant past, the Brotherhood of Makuta was once an Organization dedicated to serving the Great Spirit Mata Nui, and protecting the Matoran people. However, the Brotherhood eventually became corrupt, and believed that they could protect the Matoran best by dominating them. At least one member, the Makuta over the city of Metru Nui, was also jealous of the reverence that the people gave Mata Nui.

Makuta's plan, supported by the rest of the Brotherhood, was to attack Mata Nui with such force that the Great Spirit would eventually slip into eternal sleep, giving Makuta the freedom to take the his place as the Matorans' object of admiration. What Makuta probably did not know was that such an attack could eventually prove fatal to Mata Nui, and therefore the universe, but he went ahead with it anyway.

Meanwhile, Mata Nui saw what was being plotted against him, but by this time was too weak and injured to stop it. Instead, he took precautions that the laws of nature would keep working while he slept, and made sure that agents of his would arise to look after the Matoran and eventually wake him up again.

About a month before Mata Nui's fall, Makuta began the main part of his plan: he would put the Matoran into stasis in Matoran Spheres, where they would forget all about the Great Spirit that they revered, he would then become their savior by waking them from their endless sleep (he wanted a Mask of Time so that he could speed up this process). Makuta was in disguise as Turaga Dume, he would also order Metru Nui's robotic enforcers, the Vahki to secretly kidnap Matoran.

But the city's lone remaining protector, Toa Lhikan, became suspicious of Dume, and decided that a new team of Toa were needed. Makuta had seen in prophesies that new Toa were about to appear, and so attempted to influence Lhikan to choose Matoran other than the ones prophesized to become the new Toa. However, Mata Nui knew Makuta's scheme, and so created false prophesies. Makuta would end up steering Lhikan away from the fakes and toward the Mata Nui's choices for Toa.

Makuta hired two Dark Hunters, Nidhiki and Krekka, to deal with Lhikan; they were able to capture him, but not before he gave Toa Stones to six Matoran. Once the Matoran used the Toa Stones to become Toa Metru, the Hunters began to pursue them as well.

The Toa Metru then went to present themselves to Turaga Dume, but Dume proclaimed them imposters and ordered their arrest. While three of the six Toa were able to escape, they were on the run as fugitives from both the Vahki and the Dark Hunters, leaving Makuta the freedom to see his plan through.

As Dume, Makuta had all the remaining Matoran climb into stasis spheres "in preparation for an upcoming crisis". The imprisoned Toa Metru were able to break out and regroup with the others, and they and now-Turaga Lhikan discovered the real Turaga Dume sleeping in one of the spheres. They raced to confront the imposter Dume, but they were too late, every last Matoran had been put to sleep by then, and the Great Cataclysm was about to begin...

The Great Cataclysm
When the Toa Metru arrived at the center of Metru Nui's Coliseum, Makuta was waiting for them. He revealed himself to be the false Turaga Dume, just as what Toa Nokama called "the Great Shadow" began: Mata Nui, the Great Spirit that protected the Matoran and kept the universe alive, finally lapsed into a coma from which he might never wake up.

With Mata Nui asleep and unable to hold them back, disasters began to strike Metru Nui. An earthquake devastated the city and shattered stasis tubes in the Onu-Metru Archives, freeing nearly all the Rahiwithin. At the same time, a dual eclipse blocked out the twin suns (actually, Metru Nui was underground and the "suns" were holes in the cavern wall that let in light, the "eclipse" was both holes being plugged), one sun would continue to shine after the Cataclysm, but would be greatly dimmed.

And the effects of the Cataclysm reached far beyond Metru Nui. On the planet's surface above the city, Energized Protodermis leaked out and turned barren rock into a lush tropical island. To the south, a chunk of land broke off from an underground continent and "rocketed up" to the surface, this would land on the water and become the floating island of Voya Nui. Elsewhere, in response to Mata Nui's falling asleep, six Toa Canisters containing the Toa Mata were launched so that the Toa could go and begin the task of waking Mata Nui up again.

In the midst of this, the Toa Metru grabbed a few Matoran Spheres and started to flee Metru Nui, vowing that they would come back for the rest. Makuta tried to stop them, absorbing Nidhiki, Krekka, and Nivawk into his body in order to increase his power quickly. Toa Vakama remembered the Vahi Mask of Time that the false Dume had asked for, and finished making one from the Great Kanoka Disks that the Toa had collected. He then faced Makuta one-on-one, trying to use the Vahi's powers; however, his lack of control left both combatants caught in slow-motion. Vakama was only saved from a fatal attack of Makuta's when Turaga Lhikan jumped in the way and took the blast instead. After watching his hero die, Vakama gained the conviction to keep fighting and the ability to use his mask power of invisibility, and began using them to get the upper hand against Makuta. In the fight that followed, the Vahi fell into the sea and was lost. The other Toa Metru soon joined Vakama, they combined their powers and sealed Makuta inside a Protodermis prison which could not be broken by any means except a combination of six Toa powers.

Makuta had been defeated, but the damage had been done. Beyond the physical destruction of much of the city, Mata Nui had been sent into an endless slumber; the great protector of the Matoran could no longer protect anyone, not even himself.

Aftereffects
While Mata Nui could not or would not prevent the devastating attack, he made sure that heroes would come to restore the worst of what was lost:

The most immediate matter was that the Matoran in Metru Nui had to be evacuated safely out of danger. Fortunately, Mata Nui's choices for Toa Metru did not fail him, though it was not an easy task: Makuta had summoned the Visorak hordes to invade Metru Nui, and Toa Vakama's overconfidence led the team to be mutated into half-beast Toa Hordika. However, in the end, the Toa were cured of their mutation and the Matoran were safely relocated to the tropical island above the city that the Toa had discovered and named "Mata Nui", in honor of the sleeping Great Spirit. Once there, the Toa Metru gave up their Toa power to wake the Matoran from their stasis, becoming Turaga. But their victory had come at a price - Makuta had been freed from his prison, and would certainly be back.

Another preparation made before the Cataclysm was that the Toa Mata entered Toa Canisters that would bring them to the island of Mata Nui, so they could begin the task of reawakening the Great Spirit. However, the canisters malfunctioned and were left drifting in the sea for a thousand years. In this time, Makuta indeed returned, enslaving the native Rahi wildlife and constantly having them attack the Matoran, in order to keep them near the safety of the villages and away from Metru Nui. Meanwhile, the real Turaga Dume, Keetongu, and the Rahaga (who had been allies of the Toa Hordika) stayed in Metru Nui and did what they could to begin restoring the city.

Eventually, a Matoran named Takua gathered the Toa Stones that the Toa Metru had once made, and bringing them together shot a beam of light into the sky that finally summoned the Toa Mata to the island. They would challenge both Makuta and the Bohrok swarms that he awakened, becoming Toa Nuva in the process.

However, defeating Makuta was not the Toa Nuva's destiny, that honor belonged to another. Takua discovered the Avohkii Mask of Light, an ancient Kanohi mask said to belong to the Toa of Light who would defeat the darkness. After a journey of self-discovery, Takua realized that he was the prophesized hero, he put on the mask and transformed into the Toa of Light, renaming himself Toa Takanuva. He went to challenge Makuta himself, and in the course of the battle the two fell into a pool of Energized Protodermis, emerging as a single being called Takutanuva. Takutanuva then reopened the gateway to Metru Nui, letting the Matoran return to their city home. Afterwards, Takutanuva was crushed by the giant gate, Takanuva was quickly revived but Makuta is presumed dead. However, Takanuva is not sure of the finality of Makuta's defeat; while fused with Makuta, he got the feeling that there were bigger plans at work, ones that the Matorans' return to Metru Nui will not stop...

Recently, Turaga Dume revealed that he has discovered that the attack on Mata Nui was indeed deadly, and the Great Spirit is in danger of dying. If Mata Nui were to die, the universe would die along with him. Dume has sent the Toa Nuva to Voya Nui to find the Ignika Mask of Life that could possibly save the Great Spirit's life, but they have run up against a group of Piraka ("thieves and murderers") who are also looking for the mask. But it seems that, again, it is not the Toa Nuva's destiny to claim the mask - six Matoran followed the Toa to Voya Nui to give their help, but they were struck by lightning from the mysterious Red Star and changed into Toa Inika.

However, Mata Nui was not the only one with backup plans, the Brotherhood of Makuta made some as well. According to records that Zaktan found, if the Matoran were able to escape Mata Nui then they would eventually join with Toa, and if the Toa could not be eliminated: let them win. Let them wake the Great Spirit. Even let a Makuta die, if that was what was needed. It would all only serve to help bring about the Brotherhood's ultimate victory...