In Hell, the angels and demons fought in their true forms and with their true weapons. All that could be heard was the shouting of his brothers, of his commander bellowing orders, mingling with the screams of demons as they were blasted away by holy energies and the shrieks of his brethren as they were torn apart by their foes. Hell does not have concrete surfaces, which was good for all involved. If that were not the case, the combatants would find themselves slipping in the glowing or too-black residue of the fallen warriors.
Neither angels nor demons tire in the way that humans do. The battle carried on for days, then weeks, then months. All the while, Heaven's soldiers knew that their time could be up any second now. Dean Winchester was a righteous man, but he was just a man, and men can hold out only so long before they are destroyed.
When the First Seal broke, they felt it, all of them. A chill passed through each angel's back, and every demon laughed in a terrible cacophony. They had won their first fight.
Castiel cut off one's head mid-laugh. The joy of demons is a jarring, invasive sound to an angel, and he refused to stand for it. He knew that although they lost the First Seal, they still had hope. They still had a chance.
It took time to find Dean Winchester where Alastair had hidden him away, and it took still more time to break through the door. Even then, only Castiel managed to slip between the gates before they closed behind him.
Dean Winchester stood before the rack, his body covered in blood that was not his. Castiel spoke his name, but the man did not hear it. He continued with the work Alastair assigned him, using the skills Alastair had taught him. He continued to lose himself. Something in Castiel cracked at the sight, but he did not know what.
Castiel compressed his energies into a form somewhere between angel and human, of small enough size that he would not crush Dean Winchester's soul when he reached for him. Even as Castiel moved forward, Dean Winchester's blade cut through flesh, and the soul he tortured let out a scream unlike anything Castiel had heard before. He could sense something similar but internal at the core of Dean Winchester's self, or what he had left of it. Castiel stretched out a newly formed arm and touched Dean Winchester gently on the wrist, staying his knife.
The human looked back at him, his face brightened by the light of Castiel's form. The light did not touch his eyes.
Angels do not feel, but Castiel thought he might now have an idea of what sadness is. With an exhale of breath and energy, Castiel placed a hand on Dean Winchester's shoulder, feeling his holy power destroying the influence of Hell where the two met, burning the skin.
They blasted their way back through the door, through the battle, out of Hell. Now that he had the Winchester, Castiel could not afford to get caught. He all but threw the soul up to Earth, knowing it would find its body.
Then he turned back to his brothers and sisters and cried out the words he knew would end the battle.
"Dean Winchester is saved."