Shinobi-Nui is an island on Aqua Magna. After the destruction of the island of Mata Nui, it is the only remaining land mass on the planet.
This island is the center for Makuta Ynot's life, as no matter where he goes, what he does, how powerful he becomes, he always returns to this little piece of land.
It is first seen in Ynot's epic, Tails of the Makuta Anima. Some time after which Ynot built his base of operations here, and named it The Cabana. His reason for doing so was that after his first mission there, he was dubbed the Makuta of this island.