He'd heard Dean once say the phrase, "The straw that broke the camel's back." At the time it had seemed like a far away concept. It was something he, as an angel, would never have to worry about - something he wouldn't have been able to understand even if he'd bothered to try. His strength was immense; it was cosmic; it was infinite. He was infinite.

At least, he had been.

But now, looking down at the shards of glass scattered around his bare feet, Cas understood what Dean had said better than he ever thought he could. It felt like someone had pushed a mountain onto his chest – it was impossible to breathe – and the glass glinted mockingly up at him, edges as sharp as the sting of his stolen wings. He sucked in a mouthful of the cold, stale bunker air and it seeped down his constricted throat too slow; did nothing to get much needed oxygen to his brain. He felt cold and hollow and something dark and twisted was creeping into the empty hole in his chest. Where bright, burning grace once sat, there was now black tar and brambles, cutting him up from the inside and slowly bleeding the life out of him.

He was so...human, and it ached and burned and he was tired of this. He was tired of feeling so unnatural – trapped in this skin without his wings, unable to fly away.

As he stared down at the shattered glass around his feet – crushed and broken and such a perfect picture of everything that he'd done - Castiel understood perfectly. He couldn't do this any more. He was tired. He'd had enough. If he couldn't be what his father had made him to be then he didn't want to be anything at all.

He bent to pluck the biggest of the shards from the floor, sitting right there between his feet like someone had placed it there just for this purpose. The edges were clean and sharp and he traced them with his eyes, turning it over and feeling the sting of it splitting his skin; smears of red smudging it's pristine surface. His attention shifted to the underside of his delicate human wrist. Thick blue veins pressed up against his skin, carrying blood to the very hand that held the bloody piece of glass, and Cas pressed his thumb against them, able to feel the steady, aching beat of his heart.

'It's too easy.' A voice in his head warned. 'Easy never works. Not for you.'

He settled the edge of the glass against the biggest vein and pulled.

His skin split, clean and wide, and he was able to catch a glimpse into the fleshy insides of his own body before blood welled up and spilled over the edges of the wound. Pain was stabbing up the length of his arm, up and down in a strangely synchronized dance with the steady beat of his heart.

'Coward.' the voice hissed in his ear. 'Another sin.'

He took the broken glass in his other hand, the shard slipping between his bloody fingers, and he had to grip it in his fist to keep it steady. It cut into his palm but ignoring the pain was easy. The damage didn't matter.

The second cut hurt more and he grimaced at the hot stab of fire that shot up his arm, the glass slipped from his shaking fingers and hit the floor, breaking into yet more fragments. There was so much blood, he realized. It was under his feet and squishing, slippery and wet, between his toes.

'Such a mess.' He thought to himself, 'Dean will be furious. He just cleaned the kitchen.'

It was easy to hop over the ring of glass around his feet but he stumbled a little when the room spun and he reached out to catch himself, his side colliding painfully with the counter, bloody hands slipping on the clean linoleum surface. He leaned over the sink and rested his forearms against the cold steel basin to allow the blood to drain – he chuckled – into the drain. Less messy.

So much time seemed to have passed since he'd turned human. It felt like years had dragged by, but in reality it had only been a few months. For some reason, when he looked carefully at the gaping wounds he'd just inflicted upon himself, Cas half expected to see light shining through the cracks in his vessel, but no. Just a river of sticky, wet blood.

A wave of nausea made his stomach heave and he had to close his eyes when his head swam.

'It will be over soon.' he reminded himself. 'Just a few more minutes...'

He was just thinking that maybe it was time for him to sit down when a sleepy voice from the doorway pulled his head out of the clouds.

"Cas...? Cas!"

Dean's voice went from groggy to jarringly alert in less than half a second and before Cas could even get his own muscles to pull him up right, Dean was at his side and hauling him away from the sink.

"Fuck! Fuck!"

They were on the floor; Cas could feel cold concrete in some places and warm blood in others. His arms were sticky and his face was wet and the edges of the room were beginning to fill with shadows.

"SAM!"

It should have been louder, Cas could feel the vibrations of Dean's panicked roar shudder through him, buzzing around in his skull like angry bees.

"It's ok, Dean." He said, feeling the hunter's large hands clamp down on his wrists. He tried to pull free but his muscles were stiff and spongy. "It'sok."

"SAM!"

Dean's shoulder was shaking under Cas' head and he rolled his face to press against the man's neck, exhausted by even that small movement.

"What did you do, Cas?!" Dean moaned into his hair, lips trembling against the fallen angel. His voice was raw, like he was in some kind of agony.

He needed to make Dean feel better, needed to make him understand. "I used to bleed light." he whispered. Blackness devoured the room around him and he forced his eyes back open. "I'm not an angel...I'm not human...and this blood burns..." he grimaced, his head swimming. "...like hell fire...and I want it out."

There was movement around him but it was hard to keep track of things now. The coldness of the floor was gone and he could no longer feel the warmth dripping down his arms and if someone asked he might say he was flying. He felt lighter than he had in months; he felt numb, like nothing could touch him – like he was an angel again. Like he was himself again and he gratefully let it consume him.

But then that nasty voice was back, calling after him as he fell into the deep, dark pit of unconsciousness.

'Easy never works. Not for you.'