This story takes place during Daniel's first stint into Assendaland and Cas's time as Godstiel. I'm playing on the fact that Daniel is an Angel name to tie the two universes together. Let's say, for argument's sake, that this takes place during the off season for both shows so this never made it to the screen. In my mind Ascended and Transcended are synonymous and therefore Ascended Daniel exists in all times and knows what has happened and will happen (kinda like most interpretations of Abrahamic Gods). So there will be spoilers for later seasons of SG1, not for Supernatural.
Dean tried not to wince as the so called sinner cowed at Cas' feet begging for forgiveness. Dean didn't even know what this one had done, watching kiddy-porn or something. If he was a paedophile then Dean would have no problem with Cas' actions but somehow Dean didn't think that was the case. The super-charged angel raised his hand back to place on the 'sinner's' forehead to smite. Dean had given up on pleading with the angel some time ago. Still Cas could and would pull him out of his daily life to watch him rid the world of sinners.
"Don't do this Castiel." Dean gasped when a man in his late thirties placed a hand on Cas' shoulder, "If you continue much farther down this path the Ancients will stop you." He had short light hair and wore a white sweater with pale blue jeans. His bright blue eyes were sounded by a face held in a frown.
Castiel actually paused and turned from the sinner to the New Guy standing almost behind himself. The sinner took the chance to wiggle away and hid half behind Dean. "Daniel?" Cas sounded almost confused. "You should not be here. You are not allowed to interfere with the humans." The stranger's frown deepened.
Dean thought he might get a word in, "who's your new Angel Buddy Cas?" his eyes shifted to the new angel, "you dicks finally decide to help us fix him?" as one the two angels turned their gazes to Dean, the sinner whimpered behind him. Dean thought he had the right idea: the two blue-eyed stares were intense.
"Angel?" The new guy looked surprised, "Oma said something about that, but I didn't believe her, not really." He looked at Cas again, "Angels? Is that how you got around the rules?" Rules? "I guess it's better than what the Ori did. You, at least, don't claim to be gods, just the messengers and warriors of gods. No I'm no angel. I'm not even a god. Like Castiel here I was once a human. My name is Daniel Jackson, you might even find some of my papers online now. I cannot say more without breaking the rules though."
Cas' face contorted, "I don't answer to the Ancients. I am more powerful than them. I am doing good, why doesn't anyone see that?" there was clear exasperation in Cas's voice: he really did believe he was doing good which is what made it so sad to Dean. The apparently-not-an-angel's eyes seemed to burrow into Daniel's face.
"You are stronger than the ones who never leave earth right now Castiel, but you and I both know that just one of the Ancients could stop you. Oma asked me to try and talk to you. To warn you Castiel! If you keep this up your descent will be painful and you will never remember who you were, not even before your ascent."
Dean was vaguely aware that the 'sinner' was crawling away. Good on him: this whole thing was confusing Dean to no end. Cas had been human at one point, and not just Jimmy Novak human, but human human? "are you telling me," He glared at the New Guy, "there are other super-charged Angel-Freaks out there?" Daniel's eyes swiveled to Dean.
"Uh. I guess you could say that. I mean the proper name is Ascended Being, not Angel-Freak, but I guess it's almost the same thing." He paused for a moment, "Wait a sec, who are you? Oma didn't say anything about a regular human with Castiel." Dean heard Cas mutter 'that is Dean he is my friend' before Daniel paused as if listening to something Dean couldn't hear. Cas's head tilted to the side in the way it did whenever he tuned into Angel Radio. Amped Up Angel or no, he still listened to his brothers it seemed.
"Castiel, you know what that means, The First Ones are on their way. If you don't give up this power they will take it from you and everything you worked to achieve, including your Ascension will be forfeited." He paused for Dramatic Flair (according to Dean anyway), "That's not Oma shouting in your head: it's not Michael, or Gabriel or any other little half-ascended angels unable to manifest their own living bodies." He sounded desperate for Cas to listen but something he said gave Dean a heart attack.
What.
"What?" Dean couldn't think, itheir own bodies?/i "what do you mean, Your own body?"
"While you cannot touch me the way you touch Castiel I look the same as I did when I was flesh and blood. Castiel looks like whatever flesh and blood person he took over." He paused, "This is what I looked like the week before I died (The day I died my flesh was melting off from the inside, not a pretty sight!). Castiel's 'brothers' and 'sisters' can't even contain their incorporeal form so it won't burn the retina of those who are flesh and blood." He frowned as if just realizing that the two had gotten off topic.
"Castiel if the Ancients won't listen to me and I am as powerful as any one of their numbers what makes you think you have a chance? You, who have never left the atmosphere, think you stand a chance against the first explorers of the universe."
He turned away from Cas and Dean and threw his hands in the air and shouted: "NOT Yet you narrow minded hypocrites! Give me a chance." Dean and Cas followed Daniel's gaze to the sky where there seemed to be three storms developing all at once. Lightning flashed and a tree somewhere too close to the right of Dean exploded into fire. Cas, Dean knew, could do nothing to stop the spread of the flames; Daniel, however, raised his hand and passed it over the affected area. The flames went out. "You jerks better fix that tree! Otherwise you will have interfered with the world. The three of you can do it."
Much to Dean (and Cas's) shock three pearly white tentacles – for want of a better word – reached out of the raging sky toward the burnt tree. With three or six touches the tree was back the way it had been before the lightning.
"See?" Daniel called, "Things can be fixed! They can go Back The Way They Were. If I can convince you Hypocrites to change your mind I can help Castiel as well." With that the strange not-angel turned away from the stormy sky to face Dean and Cas again. "We will be back Dean. They have given me some time but not much." With that both not-angels disappeared: one without a sound, and the other with the sound of flapping wings.
Dean waited for five minutes before he got bored and headed back to his and Sam's motel room. Two days later Cas was back terrorising the sinners. Every few sinners or so Daniel would show up and drag Cas away. One day he stopped coming all together. Two weeks of no Daniel and Dean couldn't keep his mouth shut.
"Where's your friend Cas? Did he give up on you?"
"No Dean, he has never given up on anybody. Daniel fell. He tried to save his still living family from one of my brothers. The others decreed that he broke the rules. The fact that I have not been stopped should be proof that they cannot stop me. I am the new god." Son of a Bitch, just the luck of the Winchesters ruining everything again.
A few more months, or maybe years, passed and Sam got curious: who was Daniel Jackson? The man had said that he had papers Dean might be able to find so they started their search with that. After a few weeks of searching between hunts they found a Daniel Jackson, Doctor of Archaeological Sciences, who had been 'laughed out of academia' in the mid '90s. The brothers also found that same doctor Jackson had had three death certificates and four MIA statuses to his name by the time he was thirty five. They couldn't figure out what he did that was so dangerous: everything they found said that he was a minor translator for the Air Force.
They went on with their search as they moved around the country following this vampire or that rouge- angel until they reached some small, minor city in Colorado. When they were researching their favourite topic in the local library two men walked through the door and headed unerringly toward the brothers.
Dean's mouth fell open at the sight of them: one was wearing the dress blues of a Full Bird Colonel he had regulation sandy hair and dark blue eyes, his companion was none other than Daniel Jackson himself. He was dressed in a button down shirt and slacks but there was no mistaking the slight frown on his face. With a few quite words from the colonel the brothers were hustled outside (who brings a gun to a library, Sam said, there's no need for a gun in the library. See if Dean goes anywhere without a gun ever again! Even in the shower!) and into a blue unmarked car. Daniel sat in the front next to a hot blond air force chick and the colonel slid in the back with the brothers. The party of five drove off.
The three abductees were silent, ignoring Dean's feeble attempt at small talk. It wasn't that the older brother was intimidated by the air force personnel he just wasn't good at small talk. Eventually The colonel started his own conversation.
"Jackson, what did you do to get on these idiots' radar?"
"I don't know Mitchell, why don't you ask the idiots?" was the short reply from the front seat.
"Okay. You, Samuel Winchester, why are you looking into my friend in the front seat?" His eyes trained on the giant in the middle seat.
Sam and Dean exchanged glances and silently agreed to tell as much of the truth as they could, "Dean's met him once or twice. He was trying to keep a friend of ours, and his we think, from killing too many innocent people. He seemed to be helping for a little while, two or three months maybe, then he just disappeared. Cas, our friend, said that he fell from Grace and was human." He shrugged his shoulders, "When he met Dean Daniel told my brother his name and that some of his papers could be found, we decided to look him up."
The driving interrogation went on like that for a three more miles. Eventually the air force and Daniel must have decided that the brothers posed no threat to the security for… whatever they did and the brothers were dropped off outside their hotels with instructions to stop 'sticking your noses in' from the colonel.
"Son of a bitch! I didn't even hit on the air force chick!" Dean lamented as they drove out of Colorado Springs.