I have an old nameless great being oc. He was imprisoned by the other great beings for having powerful psychic abilities. Before being imprisoned, he had a vision of the creation of the matoran, and thought he was the being who would create them.
While in his chamber, he crafted false matoran that inherit no elemental abilities out of fragments of his mind. He soon discovered that his false matoran could escape his chamber, so he used them as eyes into the outside world. The discovery of real matoran enrages him, blaming the other great beings for "copying" his work.
My self-moc, Hautaka, is the last of his children. Hautaka is used as a tool to destroy the real matoran from the inside very slowly. He rebels, and with no memory of his creation, seeks the being who stalks his mind.
But that's just an edgy au I made when I was 12. I still think it is a creative idea but again, it may be a tad edgy for my liking.