The biggest plot twist to me? To me, it was when I finally noticed that everything on the telescope in Mata Nui foretold what would happen all these years, and I failed to notice it when I was younger. I was so upset when I finally put Vakama’s speech together and what Mata Nui had said in the Mata Nui saga…
“The Great Spirit descended from the heavens, carrying we, the ones called the Matoran, to this island paradise.” He is talking about when the Great Spirit robot fell onto the surface of Aqua Magna!
“But our happiness was not to last. Mata Nui’s brother, Makuta, was jealous of these honors and betrayed him. Makuta cast a spell over Mata Nui, who fell into a deep slumber.” This is obviously the Great Cataclysm.
“Makuta’s power dominated the land, as fiels withered away, sunlight grew cold, and ancient values were forgotten.” This was the Great War that began on Mata Nui, where the Matoran combated the Rahi.
“Still, all hope was not lost. Legends told of six mighty heroes, the Toa, who would arrive to save Mata Nui. Time would reveal that these were not simply myths - for the Toa did appear on the shores of the island. They arrive with no memory, no knowledge of one another - but they pledged to defend Mata Nui and its people against the darkness.” This is the beginning of the Mata Nui Online Game
“Great warriors with great power, drawn from the very elements themselves. Together, they were six heroes with one destiny: to defeat Makuta and save Mata Nui.” This tells of their destiny to save Mata Nui, which would happen about a year later.
And so, the greatest plot twist for me was that I did not even notice a thing about this until the very end, where they connected everything together. That was a huge plot twist for me.