The One

The One is Unicron's and Primus's daddy.

The One is the central nexus of all forces in the Universe and the source of Chaos and Order. The One is not necessarily a Transformer, or even necessarily a robot, but he created the multiverse and that's pretty awesome by itself. It is likely that he is the same deity worshipped by many humans in several Earth religions.

From Teletraan I: The Transformers Wiki, a Wikia wiki.