AN: So, there's finally a bit of action here. It's still nothing too drastic though...
"Get out of him."
The demon spun on Dean's heel and made Dean's face a mask of exaggerated fear. Dean could tell that the demon really was afraid of Castiel, but in an effort to keep the upper hand, he made the emotion appear fake. It was Dean's turn to file something away as leverage.
Shut up, the demon warned, causing that white-hot pain again. I'm still in control here. To Castiel, the demon said, "Dammit, Cas, stop doing that!"
The angel narrowed his eyes. "Expecting someone, Dean?" Castiel sneered his name, and Dean felt a twinge of hurt.
"Uh, yeah," the demon as Dean said. "Sam with food."
"He only just left. You know he won't be back soon." Castiel stared at Dean with narrowed eyes.
"Have you been following us, Cas?" the demon asked. "Why didn't you just stick around earlier? Stay in the car?"
Ignoring the question, Castiel walked closer to Dean so that they were less than a foot apart. "I know what you are."
With a cocky grin to cover up the tremor in his spine, the demon said, "Are you coming on to me, Cas?"
"I know who you are," Castiel repeated with emphasis.
"And who's that?" the demon asked, raising a suggestive eyebrow. "A dirty boy? Dammit, dude, you've gotta stop watching porn." He turned away, but Castiel grabbed him by the throat before he could move.
"Beelzebub," Castiel growled.
Cas, buddy, you know I'm still in here right? Dean shouted nervously. The angel was practically cutting off his airways with his impossibly tight grip.
"See, darling, he answered your question for you," the demon, Beelzebub, answered out loud.
What? Dean cried, a mix of confusion and fear.
"Ooh, very good," Beelzebub praised too sweetly, returning his attention to Castiel. "How did you know?"
"Your stench is undeniable," Castiel growled.
"There's no need to insult me," Beelzebub sang. "You should be taught some respect." With a lazy flick of his hand, the demon sent the angel flying into a wall. Then he rubbed his neck with one hand muttering, "Well, that'll leave a bruise," though Dean did not know whether he was speaking of Castiel's collision with the wall or his own throat.
Cas! Dean shouted. You stupid son of a bitch! he yelled at the demon.
"Well, it was him or me," Beelzebub shrugged Dean's shoulders innocently.
Castiel stood quickly, seemingly unaffected by the sudden flight. He looked with interest at the other figure in the room, listening to its one-sided argument with itself.
Beelzebub? Dean asked. I'm playing host to the devil? No way. I've met that asshole, and you are not him.
Beelzebub sighed heavily. "The devil? Oh, you ignorant boy. You've been around these Christians far too long," he said with a gesture toward Castiel, "which is quite ironic seeing as they've barely been around for any time at all."
Then who are you? Dean asked, losing his patience.
"Beelzebub, Lord of the Flies, one of the oldest and strongest evil spirits there are," the demon introduced himself with a deep bow. "Pleasure to make your acquaintance."
Would you stop moving me like a monkey? Dean grumbled, backing down as he realized how outmatched he was.
"I'm only treating you like the hair-brained ape you are," Beelzebub said as if placating a child.
Bristling at the insult, Dean forgot that he was backing down for his own good and began to raise his defenses again, but Castiel's low and dangerous voice stopped him: "Seeing as you haven't killed him yet, how long does he have?"
Dean gulped at the question, anxious for the answer. He felt his face twist into an honestly thoughtful pose as the demon contemplated this. Castiel watched with his usual stoic expression, but Dean knew from experience that he slight twitch of his lips meant he was concerned, maybe even scared. The knowledge did nothing to help Dean's sanity.
"Well, the boy is quite strong," Beelzebub was saying softly. Dean felt his hand come to his chin and a finger tap his lips as he thought. "And he is Heaven's champion after all. The amount of times you've healed him with your filthy grace has made him immune to certain demonic... illnesses as well." Beelzebub paused again before finally breaking out a sleazy smile and declaring, "I think he'll be able to sustain me for a whole month before deteriorating. That is, a month at the longest," he added with a wink.
Deteriorating? Dean cried.
"Well, look what happened to that poor man your devil inhabited," Beelzebub tsk'ed. "You'll go the same way: skin will melt and peel off, bones will crack or grind, consciousness will dwindle... And the more you fight, of course, the faster it'll happen."
Dean wanted to punch something, but try as he might, he still had no hope of moving – trying to felt like marching into a brick wall. In fact, it had never seemed more difficult to move than this moment; Dean assumed it was because the demon was in full power. In comparison to this great demonic spirit, he really was a fluffy, brainless rabbit. Refusing to feel defeat, Dean settled for screaming profanities and vowing violence when he finally got his body back. Across the room, Castiel's face darkened with rage, and his stance became more offensive. Suddenly, a shiny angel blade slid into his hand, which he gripped with white knuckles, and his eyes darkened, the blue irises pulsing. The lights of the room dimmed, but Castiel was glowing. With a roll of thunder, the large black shadows of his wings appeared on the wall behind him.
"Listen to yourself, Dean!" the demon commented happily, completely ignoring the angel. "In a handful of decades, you are going to make a wonderful demon! It's a shame Alistair couldn't break you completely those few years ago."
Castiel growled softly and vowed, "Dean Winchester will never return to Hell." His voice was gravelly and deeper than Dean had ever heard it. He was definitely scared and proud to feel the demon cringe as well.
Still, Beelzebub did not let his fear show at all as he challenged, "Oh, he won't, will he?"
I won't? Dean asked in a voice full of hope, swallowing a gulp.
"Even the boy thinks he's going back, Castiel," the demon jeered, drawing confidence from Dean's fear. The angel's name sounded disgusting as it slithered off Dean's tongue, making him wince. Now Dean wanted to smack himself because of all things to make him cry in this whole mess, the sound of Castiel's name should not be one of them.
"What did I say?" Beelzebub laughed at Dean's thoughts. "Chemistry."
In all of his angelic glory, Castiel titled his head and faltered for a moment. He asked, "Why do you wish to discuss the sciences before you are smote?"
"Oh! You're going to smite me? Interesting!" the demon trilled. "You do, of course, know that smiting me would smite Dean, right?"
Again, Castiel faltered; and yet, his show of grace did not dim. He watched Dean's body with narrowed eyes as he tried to think of something to do. Of course Castiel knew he couldn't smite Beelzebub without hurting Dean, but he had hoped the demon wouldn't call his bluff. All the angel could really do was beat up the meat suit of Beelzebub, but that would hurt Dean much more than it would the demon and everyone present knew that. There really was nothing Castiel could do without seriously harming Dean. Just showing this much of his true presence was all he could manage without scorching Dean's eyes, and any other angelic offenses would similarly maim the man. As much as it pained Castiel, he could only hope that Dean would understand if the situation unfortunately came to that.
With every second he hesitated, Castiel could see Beelzebub basking in victory. It was a disgusting sight: Dean standing so relaxed, more relaxed than the angel had ever seen the hunter before, surrounded by a deep purple aura that was unmistakably the mark of Beelzebub's presence; Dean's inimitable deep, rough voice sounding foreign due to the sneer that underlined his every utterance; the evil, cunning grin stretching across his face wider than usual and, for once, genuine, not a flimsy mask hiding the misery and self-loathing so deeply imbedded in Dean. Castiel could hardly stand the sight of his charge, his Dean, in this manner. It reinforced his desperate desire to save Dean and his sense of defeat. Taking a deep breath and allowing a deep apology to show in his eyes, Castiel stepped forward with determination and set his palm on Dean's forehead.
What are you doing? Dean gasped, wishing he could stumble backward, away from the terrifying being. Then understanding washed over him. Dean wanted to close his eyes and go peacefully, but the demon wouldn't let him. Instead, he began to whisper in a rush, though he was unsure whether he was consoling himself or Castiel. It's alright. You have to. I understand. It's alright.
But the angel stopped at the last second. Castiel reached forward instead to crushingly grip Dean's left shoulder where his handprint once was and left a new brand, searing the skin, making both man and demon wail. Beelzebub shrank away from the pain, and Dean saw an opportunity. Drawing from the pain Castiel was inflicting as a source of power, he threw all of his strength into wresting back control. Panting and gritting his teeth, Dean slowly felt himself fill in the bulk of his body again. Wasting no time to rejoice, he bit down hard on his tongue to end his scream and met Castiel's eyes in an attempt to convey that he was back. Dean let his body go limp in Castiel's grip, and the sudden lack of resistance took Castiel by surprise. Both man and angel fell back, landing on the bed; Dean almost lifeless, panting softly, jaw set against the pain coming at him from every possible angle, underneath Castiel who was still stiff and prepared to fight.
Castiel lessened the pain in Dean's shoulder, but did not move his hand. Urgently, he asked, "What was the name of the prostitute you bought for me the night we summoned Raphael?"
"What?" Dean exclaimed on the verge of tears.
"Must I repeat the question?" Castiel insisted, his voice incredibly low.
"Uh–um– Ch-Chastity! Chastity!" Dean shouted.
And with that, Castiel shut down. His wings faded, and the glow in his eyes dwindled slowly. He lowered his hand from Dean's forehead and roughly dragged him into an embrace. Caught off-guard but relieved, Dean clapped Castiel on the back weakly and smiled as he pushed the angel away. Even while simply standing beside him, Castiel did not release Dean's arm, though he did stop emitting the pain.
"What'd you do to him?" Dean asked with a grimace. He could feel Beelzebub clamoring inside him desperate to be let out again.
"I branded your body with angelic power - toxic to demons. It will not last. I'm surprised it worked at all." While answering, Castiel ripped Dean's shirt from his torso, making the man gasp and jump away, if not for the bed braced against his legs.
"What the hell, man?" he shouted.
"Your anti-possession tattoo," Castiel stated as if that was explanation enough, "what happened to it?"
On Dean's chest, above his heart, a simple but powerful anti-possession symbol was tattooed in black ink so that something exactly like this never occurred. Above the tattoo, was a painful looking red cross surrounded by a circle. The lines were jagged, indicating the time and delicacy someone used while carving it onto Dean's chest. He had no recollection of that happening, but looking at it now, he felt the pain there.
"I have no idea." Dean's voice was shaky. Beelzebub was fighting back, and it hurt. He doubled over as fresh pain erupted in his stomach, as if Beelzebub was skinning him alive with a hot poker. Castiel laid a gentle hand on his back and shoulder, trying to right him and giving him something to lean on. In his head, Dean heard the demon laugh and coo.
"Dean, listen to me," Castiel demanded. "I can't fight him–"
"Bullshit, Cas, yes, you can," Dean interrupted. "I can take a beating. It wouldn't be the first time you gave me one, after all." He tried to laugh, but it came out as a moan due to Beelzebub's attacks.
"But, Dean, I could seriously harm you. I need to smite him!" Castiel argued, losing his patience.
"Then do it." Dean forced the words through gritted teeth.
"It will kill you!" Castiel cried.
"I don't care! Kill this thing while you have the chance!"
Dean's order ended in a strangled cry as Beelzebub regained control. Castiel felt the change immediately and tried to shove the demon away from him, but Beelzebub latched onto the angel's arm and dragged him back. A long string of words from a language even Castiel didn't recognize fell from Dean's lips while his face lit up with power and evil intentions. The spell's effect was instantaneous: Castiel was bound to his spot, arms at his sides, fists clenched, legs open in a battle stance, chin up in pointless defiance.
"You should have listened to him, Castiel," Beelzebub chastised. "Did you really think I would allow your boyfriend control for long?"