This is Sinerox, the banished Great Spirit of another universe. She arrived on Mata Nui with the sole intention of destroying it completely, for reasons unknown. Rather unfortunately, this coincided with the birth of Toa Vahi. Slightly more fortunately, the two crossed paths and came to an agreement that didn't involve total annihilation of everything. Sinerox would give Vahi control of this universe if in return Vahi later helped Sinerox destroy her own. The story continues...