Serpent's Gospel
"Epapi was not the strongest god, or the most respected. He was weak whenever his belly was empty, and even mortals could hurt him. They say that one time Silver Arthur went to fight Epapi, planning to steal his divinity, but he underestimated the god and the fight went against him. So he cut open Epapi's belly and ran as fast as he could, so that when Epapi went to follow him all his meals spilled out of the cut and left him too hungry to follow. No. Epapi wasn't the strongest god.
But he had one advantage the other gods did not, because he knew how to die.
Sounds stupid, doesn't it? What good did dying ever do anybody? That's how a god would see it, at least. Now we know dying ain't the worst thing can happen. You, me, we've all done it, but gods are different. They can't die, and they think that makes them better than us. But they never realised that you can lose whilst still breathing. Look at what Aizen did to Old King Barragan. Look at what happened to Aizen, come to that.
Now Epapi couldn't be caught like they were. Anyone tried to bind him, he just died and slipped the chain. Went through the wheel of life like anyone else, built his strength back up and then took to evening the score against whoever it was that set the leash. He was just like any other Hollow; he bled easy and healed easy, he could be beaten, but never destroyed. Again and again he came back no matter what tricks they used to keep him down, and wiser he'd be for it. One time they gagged him with his own tail, to stop him from speaking the words of death. So he ate himself. They trapped him real good the next time, so he couldn't move at all, and buried him under the Earth with a legion of demons for guards. But time was Epapi was loose again, and when they checked his cell they found he'd been torn up from inside by his own young, made for that very purpose. Some say Hell was built to hold Epapi, but damn if the tricky old snake didn't slip that net too.
Epapi never stuck around long enough for things to get stale. He took tribute from his subjects, or he took them, but he never stayed in place to grind down what he didn't eat. He travelled the worlds, settling scores and making new ones, laying broods both of spirit and of flesh. When Epapi needed to be strong he sent out his young to forage for him; when he held court you could see them march to his table, great grubs who ate by the thousand and mixed 'em all together and threw it all up again, to fill Epapi's cookpot with Gillian stew. Back then nobody spared any time for the smaller Hollow, so busy they were with Epapi and his children and his armies, and for every Hollow killed by Epapi's doing two more came out better for his actions. It was a good time, by our counting.
Now Epapi could die, as I said, but he never died easy. The god's servants-not much like the ones you see today, mind, and better for that-numbered less each time he rose. So all the gods and all their servants got together and made a plan to get rid of him for good. Balancers and Yakshini, Rememberers and Arrancar, Quincy and Fomor and stranger things, they marched to put him down. The battle filled the whole of Hueco Mundo, they say; so great was the attacking army that it trampled the bedrock to sand with its marching, while when Epapi struck back the stars fled the sky, so terrible was his anger. Even now they do not shine upon that battlefield. Epapi was beaten, though he managed a bloody toll, and when the armies raised their chains he spoke the words of death and fell so that half the survivors were killed by his death-throes. But that was the trick, that when his spirit went back to the wheel they used their magic to confound it so that it would be forever lost in the dark between the worlds. So he never came back, and he floats there to this day. As time went on we Hollows forgot what Epapi taught us, and the other gods and their servants got the better of us again and again. Time was we'd go to the Living and hold great festivals, trying to make enough noise to guide Epapi back-and just let the Shinigami try to stop us! But Hollows are weak, these days, and its been a long span o' years since Epapi's Chant was heard in these parts of the Living.
But the others have grown weak, too. There are no Balancers any more, no Rememberers. No alliance. But one day a Hollow will make a Garganta and he'll stumble across Epapi, lost between the worlds. Epapi will follow the trail back to the worlds while the other gods rage in their seals and jails and in each other's guts, and he'll put things back as they should be.
Because Epapi is patient, and he knows how to die."