Old realms

The old realms are from the Marvel Comics portion of the Generation 1 continuity family.

Fragments of the old realms explode creating the universe.

According to Primus, the old realms existed before the void happened.

Fiction

Marvel Generation 1 comics

Primus explained to the Transformers and humans assembled on Cybertron that Unicron consumed every planet, every galaxy, even space itself, leaving only the the emptiness of the void. However, he missed tiny fragments of the old realms which reacted in an explosion, eventually creating the universe. The Void!