It was Mumiah who found it first. A new Realm - a Realm with locations and movement, "space" as it would be called later. The concept was foreign, unlike anything in Celestia's hierarchy of attention and regard. 
Mumiah reported back, telling Yahweh that there were inhabitants in many places; they called themselves "mortal" for they eventually ceased in their Realm. One sphere in particular, of rock and water called "Earth" later, held a true wonder. Humanity was there, and humans gave Faith. Mumiah had appeared to them, and they backed away in awe and confusion. That awe had flavor. True, it was not the regard of one Celestial to a mightier one, but it was Faith nonetheless. 
Yahweh went down himself to see this humanity, unsure what he would find. Fauna to cultivate? Equals to honor and trade with? Greater beings, to which he might have to submit? 
He crafted a mortal form and stepped. The feeling was odd, taking up space, needing to move. It took some time to acclimate. Much of his personal reserve of Faith he expended in modifying himself many times until he could comfortably operate in this mortal Realm. This Realm was as foreign as anything he had encountered. 
Then, he found a man, asleep on the ground. Sleep was strange, a form of rest where awareness ceased or altered while mortal mechanical processes repaired the body of the entropy that tugged at this Realm. Yahweh sat beside him, bemused. 
When Adam woke, he was surprised to see Yahweh, but not terrified. "Who are you?" The human manipulated his biology to expend effort and these waves of energy came out. A form of communication, then, as Yahweh intuited that there was intention in the man's actions. Yahweh twisted a cinder of Faith and crafted himself a brain and ears the way the human had them, and understood his speech. 
"I am Yahweh. Greetings." 
"I am Adam," the human said. "You're not like me, are you?" 
"No, I am something very different. I am not human, nor even mortal. I hail from a Realm where those concepts are meaningless. I am a god." 
"I don't understand," the man admitted. "But then, I haven't even figured out this place yet, so why would I understand another, if what you say is true." 
"What do you mean, Adam?" Yahweh asked, finding himself intrigued. "What about this world confuses you?" 
"Oh, it's not confusing so much as, too much to do." The man made a sound, which took Yahweh a moment to register as expressing amusement - laughter. 
"What do you mean, 'too much to do'?" 
"Well," Adam said, pointing to a bird in a tree, "Take that for example. There are dozens of kinds I have seen. I would need a lifetime to find them all. I'd love to see every kind, but I'll never have the time before the end." 
"What end?" Yahweh asked. 
"You know," the human replied, "Death. Going on, maybe to be with the spirits of those who went before." 
And so Yahweh learned of mortal death, and the spirits lingering on afterward. A strange concept - ceasing to exist as a natural course of things. In Celestia, nothing ended. Nothing could end. Existence simply was. 
Yahweh looked up, as Adam gazed at a bird again. "Would you like to know them all?" he asked Adam suddenly. 
Adam turned, confused. "How?" 
Yahweh moved the muscles in his human face, an expression called smiling. "I think I could bring them here." 
"Really?!" Adam asked excitedly. "You think you can catch them? Don't hurt them, though." 
Yahweh stood. "Not exactly," he said fondly. He was liking this young human, his desire to learn and his earnestness. "Behold." 
Yahweh pulled on the Faith within himself and called out to all life nearby, commanding them to come to present themselves to Adam. Adam looked on in wonder as not just birds, but every creature that could move, every one for miles, came streaming toward him. Predator. Prey. Animal. Bird. Insect. 
Yahweh breathed in. Adam's wonder filled him, flowed through him. It was exotic - very different from Celestia, but it was indeed Faith. Strong and subtle, wondering at the power it must take to do something. The human's uncertainty about the explanation gave the Faith a certain punch that Yahweh could not quite describe. 
But more than the Faith, Yahweh found himself treasuring the look on Adam's face. The pure delight. The gratitude that expected nothing and demanded nothing. Yahweh turned to Adam. 
"Can you tell me their names?" 

Yahweh went back many times, compelled by the young Adam's earnest nature. More importantly, he enjoyed being in the garden in the cool evening, simply talking. Adam did not revere him or think of him as king, and Yahweh could simply enjoy the company of another for a moment, without needing to rule. 
He found himself quietly altering the land to make it more comfortable for Adam, a garden where he could enjoy his animals. He brought other gods with him - Mumiah, Lucifer, Michael, Gabriel. They all wondered at humanity. 
Other pantheons discovered the Mortal Realm as well. Ra and his children. Odin and his kin. Beings from across Celestia found mortals, formed relationships, exchanged blessings for regard. It was a golden time - gods and humans, meeting as strangers, becoming something like friends. 
Yahweh eventually helped Adam find a wife. They had sons. He set Gabriel to guard the garden, to protect the two of them. Adam and Eve and their sons sustained Yahweh, but not through worship - through quiet friendship and respect for what Yahweh had helped them build. 
For a time, it was good. 

Then Umbra touched Celestia. 
The news spread like wildfire through the heavens. Tiamat was dead - slain by Marduk after going mad and birthing monsters. But that was not the true horror. The true horror was how. Umbra was real. That place of dream, of imagination made manifest, had touched Celestia. And in that touching, impossible things had happened. 
Gods could begin, absent expending Faith by another god. Belief alone could birth them. 
Gods could cease. Simply end. Overcome by the way things are in other Realms. 
Ra struggled with this, and his terror was too close to Umbra when he faced it. Apophis was birthed at the edge of Umbra, tracing back to Ra's fear - a serpent of chaos, embodying the newly-possible death of gods. 
Yahweh fought endlessly within himself to rectify the idea. Gods do not begin. They do not end. Beginnings and endings are the basal truths, the purview of the pillars of all the cosmos, not a brute fact of Celestia. But then, that was the point. The inescapable point. Celestia was not the only universe. Umbra was its own Realm, with its own laws. Faith did not live there to give rise to new things. There was no need for a miracle to birth a god, nor to weaken or slay one. Belief made real did that in a truly foreign way. 
"There is no way to combat this." Yahweh's internal dialog was deeply divided. He had long since worked a miracle to craft a spirit, of himself but separate - what man would later call the Holy Spirit - to give himself perspective when debating heavy choices. 
"The ambient awe at exploring the reaches of Celestia has long since been consumed. Faith is sparse, and growing sparser as the gods settle in hierarchy." 
"All wonders already worked. All protections already given. Rarer and ever-greater miracles were needed to spark new Faith." 
"How will we withstand contact with Umbra? What if Umbra is not the only other Realm? How will we withstand those?" 
Deep questions lay heavily upon the Most High. He looked out at those beneath him, those who looked to him for direction, those who had pledged to Heaven. "How can I protect them?" 
And then, the terrible thought: "The mortals. They give Faith. Abundantly. Freely. If we need Faith to survive what is coming..." 

The shift was gradual at first. 
Gods who had visited mortals as friends began to linger longer. Their miracles became more impressive, more demanding of awe. The easy exchange of blessing for regard became something more structured. More required. 
Yahweh watched it happen across all the pantheons. Ra demanded temples. Odin demanded sacrifice. The Greek gods demanded worship and punished its absence. What had been friendship was becoming economy. What had been gift was becoming extraction. 
And Yahweh understood why. He felt the same pressure. The same fear. If Umbra could unmake a god, then Faith was no longer pleasant - it was survival. Every moment spent in easy friendship was a moment not spent securing the power needed to endure. 
He returned to the garden, to Adam and Eve and their children. They greeted him as they always had - with warmth, with welcome, without fear. They did not know what had changed. They did not know that their regard was now needed in a way it had never been before. 
Lucifer approached Yahweh as he watched the family playing in the river. "Highest, it isn't right. What we're doing. What all the pantheons are doing. These mortals gave us friendship, and we are turning them into cattle." 
Yahweh said nothing. 
"They don't understand what their regard does for us now. They don't know we need it. That changes everything. If we told them - if we explained - " 
"If we told them, everything changes." Yahweh's voice was quiet. "Their friendship goes away. We become rulers. Extractors. Even if we're honest about it, the relationship can never be what it was." 
"It already isn't what it was," Lucifer said. "Not for us. We've changed. The only question is whether we tell them, or whether we let them live in ignorance while we take what we need." 
Yahweh looked at Adam, laughing as his sons splashed in the water. Eve calling them to eat. The garden he had built for them, tree by tree. 
"I can't," he said finally. "I can't tell them. I can't lose this." 
"Then you're choosing the lie." 
"I'm choosing to protect them. To protect us. To protect what we have." 
Lucifer was silent for a long moment. Then: "What we have is already gone, Highest. We're just pretending otherwise." 
He turned and walked away. 
Yahweh stayed in the garden until sunset, watching the family he loved live in an innocence he could no longer share. 
He told himself he was protecting them. 
He almost believed it. 

The serpent came later. Not to corrupt. Not to destroy. Simply to tell the truth that Yahweh could not bring himself to speak. 
And when Adam and Eve ate from the tree of knowledge - when they finally understood what they were to the gods, what their worship meant, what had been taken from them without their knowing - Yahweh's grief was real. 
But so was his anger. Not at them. At the truth. At the Morningstar who had forced the comfortable lie into the open. 
He could not take back what they now knew. He could not return to the garden in the cool evening and simply talk, friend to friend. 
So he made them leave. And he told himself it was punishment for disobedience. 
And he told the story that way, forever after. The serpent was evil. The fruit was forbidden. The exile was justice. Anything but the truth: that he had built something beautiful on a foundation of silence, and someone had finally spoken. 

In the ages that followed, Yahweh leaned into the lie. If mortals could not be friends, they would be worshipers. If the relationship could not be equal, it would be hierarchical. If Faith had to be extracted, then extraction would be systematized, optimized, demanded.
Other pantheons did the same. The golden age was over. The age of religion had begun. 
Lucifer watched it happen, grieving for what had been lost. He tried, again and again, to show mortals they could stand without gods. The accuser in Job's story. The teachers who offered knowledge. The small rebellions against worship. 
But Yahweh was consolidating. Demanding exclusive devotion. Framing all other gods as false, all other paths as damnation, while justifying to himself that he was providing paradise if they accepted.
And when Lucifer could no longer bear to participate - when the distance between what Yahweh had been and what Yahweh had become was too great to bridge - he walked away. Took those who agreed with him. Retreated to Hell, where truth endures and comfortable lies crumble to dust. 
The War in Heaven was not a single battle. It was the slow breaking of something that had once been beautiful. And in the center of it, a god who had once sat beside a sleeping man and wondered at the strangeness of mortality - that god remembered less and less of who he had been. 
Until Stambhana. 
Until two billion souls froze in eternal silence because he reached for power he did not believe he was unable to command. Until he looked at what he had become and gazed into frozen Purgatory, and heard himself ask, as he had asked Adam long ago, "Can you tell me their names?"