Mata nui was a large island home to the metruans. It was later destroyed by a giant robot waking up to go to school. When the robot crashed, it activated its camouflage, making it invisible to the zyglak and makuta, but it didn't work since the island started to look like an island so the makuta attacked but the Toa didn't defend the matoran because 1. They were lazy 2. They blew when they hit the island and had to be rebuilt by the turaga and 3. They were lost. Eventually with the help of the Bohrok and makuta, they destroyed the island and makuta left for school. Everything on mata nui died.