I always imagined the continuation of Bionicle being another flashback like with the Toa Metru and Toa Hordika only this time going even farther back, to a time before The Shattering (breaking of Spherus Magna) to a time I call the god wars. The idea is that it is a war between the great beings which are not that different from normal toa or glatorian, just way more powerful. On the one side Mata Nui led the battle against the darkness which was secretly headed by Makuta who was acting as a double agent. Also on the side of light where Toa Lhikan and Toa Dume who, together with Mata Nui, made the War Council. The giant robot was one of three however one two were destroyed (one vaporized the other scattered across the planet to later be rebuilt by Mata Nui on Bara Magna). These giant robots were created to end the war, one for each of the war council, however as the others were destroyed Mata Nui was the only one to transfer into his, leaving Dume and Lhikan to hitch a ride inside. Dume transforms into a turaga to lead the matoran and Lhikan stays to protect them. Meanwhile Mata Nui in his new body narrowly misses The Shattering (which was caused by the spear of fusion) with Makuta secretly hiding on board.