Machinery shifted. For a brief second, the entire body of the Ancient was still before the gears once more burst into motion. With apocolyptic concussions, worlds cracked and crunched. They compressed to the size of a pinhead, smaller, and all who were on them were devoured by the pinpricks of oblivion. The Ocean churned as worlds were displaced into the void and obliterated. Those on such worlds had no such fate, though. Shards of worlds were compressed to metal and formed into hulking mechanical shapes. The souls of those who lived on the world were bathed in nothingness. The songs of Ketarus Mechanicus wiped them clean, sinner and saint alike. Spirits of mechanical oblivion, the machine spirits poured into the war-machines. They were the Behemoths of Oblivion.
They were disgorged from nothingness, singing the music of the gears. Colossal, implacable, they hummed across the Ocean, the points of oblivion at their core. When they encountered ships the machine-spirits surged forth; grasping victims and materials, they pulled them back to the Behemoths of Oblivion. Ethereal, the machine-spirits seized elementals and flesh alike. They were fed into the Behemoth's Oblivion Hearts, where they became energy for the Grinding Gears. Those who submitted willingly were not consumed, but frozen: in tubes of crystal their minds were stilled and their bodies frozen. They were held, dormant, until the end was over, and the Kalpa could be renewed.
The Behemoths and their crew bound to the mind, such as it was, of Ketarus, he hung immobile in front of the void. With another act, another flywheel spun down, he sang to the minds of all living beings in the Kalpa.
Behold! I am Ketarus Mechanicus, the Grinding Gears of Oblivion. Your gods have failed you. Their foolishness and violent natures have led to my emergence. This Kalpa is over. Oblivion is coming. All things must end.
But I offer you all a chance. Your gods would risk the end of all. You worshipped them, and they repaid you with death and sorrow. There will be a new kalpa. One without murder. Without sorrow. Your gods demand temples to stave off the end of their age, becasue they are weak and cruel. They gives words of salvation they cannot deliver. Witness! Some had fled a previous Kalpa, abandoning their peoples to do so.
I offer another way. Even now, my servants transverse the ocean to your worlds. Go to them. When this universe is undone, you shall be preserved, and assume new life in the next. But if you fight, if you struggle, I have no choice to rend you into nothing, and never again will your mind be known in a kalpa. When your gods demand worship, lead your prayers to me. Dedicate your temple to the Machine, for that way lies harmony, that way lies perfection.
All things must end, but you may yet begin anew.
And all who heard could not help but feel a spark of agreement, for that clattering, whirring song was copper-sweet and pure...
Major act plus an act or two if necessary - Crush the worlds and transform them into the metal Behemoths Of Oblivion. Those on the worlds were purified into mechanical spirit-beings designated machine-spirits. These are bound the Mechanicus' mind, and gather up unconverted beings and process them. Those who refused the Offer are fed to oblivion and oblitered, turned into energy that is fed to Ketarus. Those who agree are either stored in dormancy inside the Behemoth or are converted to machine spirits as they wish.
Act - speak to the entire universe, manipulating their minds to turn from their old gods and turn to Ketarus instead.
Keep at least 2 Acts and 1 major act in reserve.