The Great Cataclysm was a major event within the storyline of LEGO BIONICLE franchise. It is the collective name given to a series of natural disasters that occurred one thousand years before the storyline's "present day", when that universe's guardian, the Great Spirit Mata Nui, fell unconscious (to be more exact, when Makuta caused him to fall asleep). Much of the storyline revolves around the Great Cataclysm, its consequences, and the attempts to repair the damage caused by it.
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 Matoran's 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. Makuta launched this attack in the wake of his bodyguards, the Toa Hagah, rebelling against him; before the Brotherhood's corruption could be exposed any further.
Mata Nui would linger, badly injured, for three hundred years afterward before lapsing into unconsciousness. As this happened, without his intervention to prevent them, a number of natural disasters struck at once, all over the world...
The city of Metru Nui was hit by an earthquake and an eclipse of both of its "suns" (the city is underground, and both of the holes where sunlight showed through the surface were blocked). As a result, the city was reduced to ruins and nearly all of the Rahi beasts kept in the city's Archives were freed.
The Makuta over the region, the one that had made the initial attack, however, had planned for this. About a year and a half before the disasters struck, he kidnapped and impersonated the city's leader, Turaga Dume. In this position, he ordered that all routes out of the city be closed and sent the Toa who protected the city out on missions from which they never returned.
About a month before Mata Nui's fall, Makuta had all the Matoran put into stasis in Matoran Spheres, either by force through his Morbuzakh plant monster or the Vahki, or on "Dume's" order. The plan was that in the spheres, they would forget all about the Great Spirit that they revered; and Makuta would then become their savior by waking them from their endless sleep. While this plan almost succeeded, the Toa Metru rescued the spheres and woke the Matoran inside, sparing them from Makuta's lies.
It was originally thought that Makuta's actions at this time were what caused the Great Spirit to fall asleep, and only later revealed that the actual attack came three hundred years earlier.
On the planet's surface above Metru Nui, energized protodermis leaked out and turned barren rock into a lush tropical island. The Toa Metru soon discovered this island and named it "Mata Nui", in honour of the Great Spirit, and it became a refuge for the Matoran of Metru Nui.
To the south of Metru Nui, 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, stranding all who lived there. Voya Nui later floated north over the location of the Pit, and the city of Mahri Nui broke off and sank, anchoring the island in place.
The cavern where the Order of Mata Nui had banished the world's most vile beings, called the Pit, flooded and allowed the inhabitants to escape to the surrounding sea. However, the Cataclysm also did something to the water, making it mutagenic and turning all surviving prisoners into waterbreathers; thereby confining them to the ocean. Voya Nui later floated into this area, and its major city of Mahri Nui sank into the criminal-infested waters. Also, the original Hydraxon died in this catastrophe.
The underground continent that Voya Nui broke from rested on top of another cavern, the "universe core". With Voya Nui breaking through the "ceiling" to the ocean above, there is now a waterfall pouring down into the core and creating a swamp.
In response to Mata Nui's falling asleep, six Toa Canisters containing the Toa Mata were launched from an unknown location so that the Toa could go and begin the task of waking Mata Nui up again.
Though Mata Nui still sleeps, all is not lost. The following tasks are ones known to be necessary to restore damage caused in the Great Cataclysm:
- Save "the Heart of Metru Nui"
One of the most immediate matters in the wake of the Cataclysm was that the Matoran in Metru Nui had to be evacuated safely out of danger. Fortunately, while Mata Nui was still awake he sent six Matoran on the path to become the Toa Metru who would do the job. But 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 of Mata Nui (named in honor of the sleeping Great Spirit).
- Save the Great Spirit's Life
Turaga Dume has recently discovered that the attack on Mata Nui was more severe than had ever been expected, and the Great Spirit is dying. If he should die, than the universe would die with him in a matter of days. To prevent this, Dume sent the Toa Nuva to the island of Voya Nui, where the Mask of Life was hidden; only this could restore Mata Nui's life energies. But the Nuva were captured by a group of Piraka who wanted the mask for personal profit, and a new team of Toa Inika were instead empowered to claim the mask. The Inika are now pursuing the Mask of Life down to Mahri Nui, where it has been claimed by Barraki warlords. the mask reacted to their touch and sent a burst of light towards the stone cord where the Toa Inika were traveling from, changing their forms to breath in the Pit. They managed to retrieve the mask and its carrier, Toa Matoro, swam towards the Universal Core. He then heard the mask telling him to put it on. And so, he and the Ignika became one, restoring Mata Nui to full health when he was about to die.
- Restore the Land
Several lands damaged and altered in the Cataclysm will need to be restored to their pre-Cataclysm state:
Mata Nui: The tropical island needs to be restored to the bare rock it once was. Foreseeing the need to do this eventually, swarms of Bohrok drones were nested below the island and programmed with this very objective. Unfortunately, Makuta had activated them early, while the Matoran were living there. They were stopped by the Toa Mata, and their failsafes (elite Bohrok called Bohrok-Kal) were defeated by this same team after they had become Toa Nuva. Now that the island is uninhabited, the Toa Nuva have reactivated the swarms so they can complete their task in peace.
Metru Nui: The City of Legends will need to be restored to proper working order. While its population lived on Mata Nui for a thousand years, Turaga Dume, the Rahaga, and Keetongu worked together to repair what they could. Eventually, Toa Takanuva defeated Makuta and reopened the path between Mata Nui and Metru Nui, allowing the Matoran to return and begin the large-scale restoration efforts.
Voya Nui: According to Makuta, the island of Voya Nui will need to return southward to its original place in the underground continent. He claims that cutting it loose from its anchor of Mahri Nui will be sufficient to cause this, but that doing so will doom the Matoran living in both places.
Besides the actions taken above, the Staff of Artakha's power to repair has been used on the entire world, thereby fixing most of the damage. However, its power could not breach the shields of the "universe core", so it still requires repair.
- Awaken the Great Spirit
Finally, the cause of the Cataclysm will need to be addressed - Mata Nui's coma. This task is known to fall to the Toa Mata (now the Toa Nuva), though how is unknown. When the Cataclysm first occurred, the Mata entered a set of Toa Canisters and were launched from Daxia with the destination of Metru Nui. Anticipating that the city might be occupied by enemy forces, the intention was to use the island of Mata Nui as a landing point (as the path between these two locations was fairly unknown and therefore less likely to be guarded). However, the canisters malfunctioned and drifted aimlessly for a thousand years until Takua sent a beacon from Mata Nui; during which time the Toa Mata lost their memories of their lives before entering the canisters. They would have to do a number of tasks that were placed on a scroll in the Great Temple. They had to unleashed the Bohrok swarms on Mata Nui, retrieve the Staff of Artahka (see both above), quell a fury of volcanoes, steal the Heart of the Visorak and take measurements of the Red Star. Their final task was to return to Karda Nui for unknown reasons.