Title: What Archangels Have Joined Together
Characters/Pairings: Dean/Lucifer, Sam/Gabriel
Spoilers: Season 5 in general, 'Hammer of the Gods' in particular
Warnings/spoilers: Nothing I can think of.
Summary: Response to this prompt: Gabriel/Sam, Dean/Lucifer - Gabriel really didn't die, instead he bound Dean and Lucifer together... this may be his best or worst prank ever.
Author notes: This was originally posted as comment fic, for the All Is Fair In Love & Prank Wars fic meme.
What Archangels Have Joined Together
"I'm gonna kill him," Dean growled out, with certainty.
"I have already tried to do so," Lucifer said, looking about as pissed as Dean felt. "It did not work."
Sam was sitting there trying to look supportive and concerned, but a small grin kept breaking out before he schooled his face back into a more appropriate expression.
Cas just watched them warily, but contemplatively, like Dean and Lucifer were some kind of science experiment gone interestingly wrong.
"So… you're sure you're… bonded?" Sam asked.
"Yes," Lucifer said with finality, while Dean snarled, and Castiel had to grab him by the arm to stop him doing something, like maybe punching his brother. "My Grace is tethered to his soul. It is unmistakeable."
"What does that mean, exactly?" Sam asked.
"When two angels develop a significant regard for each other it is possible for them to join their Grace," Castiel explained, forcing Dean back down onto the bed next to Lucifer. "They become aware of each other's emotions and state of mind, and in some respects behave as one entity. It is considered the ultimate expression of their attachment."
"So basically, Dean and Lucifer are angel-married?" Sam clarified, looking both aghast and desperately amused.
"There are some similarities," Lucifer allowed. "But the creation of a bond is far more profound than any human ritual. Your brother and I will be co-dependent for all eternity. I don't understand how Gabriel managed this. It shouldn't have been possible."
The last sentence was said with an enormous scowl, but for the rest of the explanation he had spoken in the same intent reasonable professor-voice that Sam often used when he was explaining things, and with Sam peering at him with intellectual interest it made the two of them suddenly appear disturbingly alike.
As though being angel-married to the Devil wasn't enough, the guy also reminded Dean of his brother. Awesome.
"Gabriel is very resourceful," Cas observed. "He has displayed great cunning and creativity in remaining hidden for so long. It does not surprise me that he is capable of a feat believed to be impossible."
Cas's words made Dean want to punch him, but it wasn't his friend's fault he was in this mess.
"I'm gonna kill him," Dean said again, instead.
A thought struck him and he whirled on Lucifer, stabbing a threatening finger in his face.
"You better stop trying to make my brother say yes, you son of a bitch," he declared ferociously.
Lucifer was unmoved by having a finger waved in his face.
"It should be unnecessary. Since Gabriel bound us, the bond appears to be somehow easing the effect that my Grace has upon my current Vessel. The damage has been healing itself."
Dean took a closer look at Lucifer's face. Sure enough, the scabs were smaller and fewer than they had been before.
"Wait," Sam suddenly stood straight, and stared at Lucifer sharply. "You don't actually need me as a Vessel, anymore?"
Sam's expression cycled through several emotions: chagrin, anger, suspicion; before he looked resigned and annoyed.
Lucifer just watched him in amusement.
"Why," Dean asked slowly, looking at Lucifer with narrowed eyes, "are you so amused?"
Lucifer turned serene eyes on him, clear and bright. Something in Dean tugged at the peacefulness of that expression, and he stomped on it ruthlessly.
"Angels have occasionally bonded with humans before," Lucifer told Dean smoothly. Dean could feel him building up to something. "It was found that a bonded human cannot be taken as a Vessel."
While Dean was absorbing this, Lucifer added, "Gabriel has attempted to disguise the tie between he and Sam, but did not quite succeed."
There was a moment's silence as Dean put this all together.
"You're telling me the fucking Trickster has BONDED to my BROTHER!" Dean roared, bounding to his feet in rage.
Sam looked abashed, and a little guilty, like he always did when he'd done something particularly frigging stupid.
"He told me that Lucifer couldn't take me as a Vessel," Sam said defensively, mumbling a little.
Dean spluttered wrathfully, too incensed to form words. He flailed impotently.
Something heavy and soft and warm fell across him soothingly, and for a moment Dean felt comforted, before he realised that the bastard archangel next to him had curved a wing around him to calm him down.
Dean shook it off and stalked away from Lucifer, back to snarling.
"Oh come on, you've got to admit, it works," Gabriel griped, appearing out of nowhere.
Dean let out a growl and dove at him.
Castiel promptly wrestled him to the floor, and when Dean didn't stop struggling even when he said "Dean," in a meaningful voice, sat on him.
"Lucifer can't take Sam as a Vessel, Michael can't take you as a Vessel, and if Lucifer tries to take over the world, you can make his life a totally different kind of hell," Gabriel pointed out. "Hey presto, apocalypse averted!" He looked enormously pleased with himself.
Dean tried to push Cas away, but the angel was seated on the small of his back and wasn't going anywhere.
Gabriel watched his efforts.
"If you try to kill me, you'll hurt Sammy," he told Dean. He turned to Lucifer. "And if Sam is hurt, Dean'll do his absolute best to hurt you, bond or not."
Cheerfully he snapped up a lollipop and sucked on it, looking like a kid whose project just came first in the science fair.
To Dean's disgust, Sam was watching him with a reluctantly admiring expression, like he didn't like Gabriel's methods but was kind of impressed by what he had achieved.
Gabriel winked at Sam, who blinked, and tried not to smile back.
"Just for the record, I hate your guts, and just because you're my new brother-in-law doesn't mean I'm not going to try and make your life hell," Dean told Gabriel resolutely.
"Oh, I'll be watching my back around you and Lucifer for a while," Gabriel agreed, not in the least worried. "But hey, you've got to admit, what I did? Pretty damn awesome."
"Oh my God," Sam blurted, suddenly grey with horror. "Satan is my brother-in-law!"
Lucifer simply smiled at him.
"I hate my life," Dean said, with feeling.