"When the forty-seven Spheres align, a perpetual conflict will culminate upon a world forged from Chaos. And the weak shall perish in the shadow of a Rising Darkness." (Covenant of Primus)
It was a time of reckoning on the Earth. The waters of the Earth were no more and have been for billions of years. Other than scant few microscopic life forms, no other life exists. Above, Solar luminosity has become much greater, but a terrible sight was to be beheld. Gone were the days of the total eclipse, when the Lunar shadow completely obscured the Solar disk. In its place was something like a terrible eye piercing through the Earth.
This was going to be the last rendition of a terrible eye piercing through the Earth, for on the other side, the Lunar body was being devoured by the red giant. On top of this was an extraordinary syzygy of forty-seven celestial bodies; forty-seven such masses were in astronomical alignment. What was once a dormant planetary core awakened to usher in its terrible chaos.
"I AWAKEN!"
The Lunar body became devoured fully by the red giant.
"The taint of Primus is no more!" declared this embodiment of chaos.
Not long after the Lunar body became no more, the parent body followed suit.
"PARASITES!" declared a rather animated force of nature that was once a planetary core, still sensing the scant few microscopic life forms as the parent body exploded.
Thus, time has reverted once more to what was before the beginning. Facing one another across the vastness were twin forces of nature that retained their respective physical forms despite being able to transcend them. These were no ordinary forces of nature, though, for they were rather alive.
"Your taint is no more upon me, your line of Primes has fallen, all your creations have fallen into the Chaos, and by my will alone have all parasites shared such fate!" declared the incarnation of Destruction.
"So have your followers, Brother! We are merely back to what was before the beginning!" declared the opposite, the incarnation of Creation, who then charged.
Thus, did Primus and Unicron do the indefinite clash of the gods once more.