Unicron is the eternal arch-enemy of his twin brother Primus. Also known as the Lord of Chaos, the Chaos Bringer, and the Planet Eater, he is dedicated to consuming the multiverse. His massive form is powered by the consumption of planets, moons, stars, and even the very fabric of existence. Unicron will not be sated until his ultimate goal is attained: to bring an end to the annoying creation boasting independence around him, and find peace by becoming the living center of a swirling, infinite torrent of nothingness at the end of all things.
To undertake this seemingly overwhelming task, Unicron is able to travel across realities at will, a meandering plague upon existence itself. Integrated into his systems are incomprehensible quantum computers which calculate probabilities forward and backwards in time, in perpetuity, giving his processors an ever changing, evolving map of the multiverse. With these abilities at his disposal, Unicron has thus far devoured approximately 22.56% of known universes. Seen at a detached distance from the multiverse, this collective "Unicron Phenomenon" acts with the characteristics of a virus or plague seeping through reality and succeeding where it can, and retreating when it cannot. Various permutations of Unicron can spawn into existence outside the trappings of the larger entity, hailing from a more mundane origin but possessing the same consumptive traits.
The only thing that he fears is Primus's essence, contained inside the Matrix. To a being of chaos and uncreation, this font of life is a poison.
Frequently, Unicron will make deals with lesser beings, promising them vast new powers in exchange for their servitude. These minions are sometimes stripped entirely of their free will, but others follow him willingly. Service to Unicron, however, is a double-edged sword, for it causes insanity and loss of self. And in the end, Unicron's plans ultimately call for their consumption as well.