Supreme Being

The Supreme Being is even beyond the Three Beings. He resides outside the Mirror Universe. The Messenger makes reference to the Supreme Being, that the purpose of the Being in creating the Mirror Universe was to honor the Supreme Being.

Spoiler:

To understand the Supreme Being, one must have a great knowledge of allegorical works. The Supreme Being is the Judeo-Christian God Jehovah, while the Being is the creator of the Mirror.