After running through hell's carousel of damned souls, Cas and Dean finally stopped at a gritty metal door, no markings save for a thick nondescript ring melded into the center.
Dean pulled on it as hard as he could. It wouldn't budge.
"This is it?" Dean asked doubtfully.
Cas looked at Dean and nodded.
"Get ready," he said, then stepped forward and, instead of pulling, used the metal ring to knock against the door. Dean rolled his eyes. He set his feet, raising his knife as the door slid open slowly.
He waited for a couple seconds before shoving hard against the door, hoping to knock the demon behind it off balance. The desiccated, skeletal body of the demon's true form rocked back on its heels for only an instant. It screeched and narrowed its black, slitted eyes and attacked with razor sharp claws. Thunder and lightning struck loudly overhead just as Dean ducked and aimed for its gut. The demon shifted and pierced a claw into him just below the armpit and Dean cried out in pain. He suddenly felt Castiel's presence beside him and within the blink of an eye the feral demon was off him and slammed against the wall, writhing and spitting.
Dean collapsed, huffing in agony over the sharp stab wound, and stared up at his angel. Cas was standing beside him now, in the hallway, using one hand to hold the demon up.
The demon began laughing, its spindled extremities shaking with twisted mirth.
"What're you gonna do, smite me? You're in hell," it hissed. Another streak of lightning overhead and Dean could see Castiel's stoic expression. He couldn't figure out if the demon was right - whether angels could smite demons in hell or not.
"Dean. The blade," Castiel commanded, eyeing the disgusting, mangled demon on the wall.
Guess not, Dean figured. He handed the weapon over from where he was sitting on the repulsive wet, dirty floor. Cas looked down, curious, and realized Dean was so injured he couldn't get up. The angel moved faster after that, approaching the demon quickly, the blade in hand.
"Wait- no!" The demon yelled just before Castiel unceremoniously - almost casually - sunk the knife up to its hilt into the demon's flesh. Thunder cracked and roared overhead, drowning out the ungodly screams as light crackled and fizzled inside the wretched form before extinguishing entirely.
A black charred heap landed on the floor.
"So..." Dean said, leaning against the stone wall, pressing down on his injury as hard as possible. He looked up at the storm overhead. "This Limbo? That why you could, uh..."
Cas watched Dean, brows furrowed with concern.
"Yes. Anything I do now as an angel will be discounted given Lucifer's presence in this section of hell."
"Cool," Dean huffed winningly, jaw clenched. He gestured, uncoordinated, to the demon's remains. "You can't smite demons here though, huh?" he asked, breaking into a sweat.
"I would need more of heaven's forces with me in order to do so."
"Can you heal?" Dean gritted out. Cas knelt down and pushed Dean's hand away from his side, pressing his palm against the wound.
"Yes," he whispered softly, almost kindly, as a small light emerged under Castiel's hand and healed the injury.
Dean took a huge breath, then a few more.
"Are you ready?" Castiel's palm still laid against Dean's side, an unconscious gesture of comfort. Dean took it, swallowing and nodding before reaching for his angel's arm to help him up.
"Right as rain," Dean replied gruffly, getting up and cracking his back.
Silent and synchronized, they ran on into the depths of hell.
