He'd felt the strange energy slowly pouring into him, it was new and nothing like what he'd ever experienced. Had he passed out again? Cas struggled to open his eyes but his mind was the only that would move for him. 'Who's there?' He asked inwardly and the silence that replied shook him to his core. There was a slow familiarity dripping with the rest of the energy that filled his mind's cavity. 'Death?' The realization made his mouth run dry and his stomach threaten to purge its contents. 'Am I dead? Did I… did I fail?'
"Almost." Death replied calmly though Cas could feel the irritation. "But I can't let that happen."
'What are you doing?' Cas asked as a tingle started in his fingertips and surged up his hands into the rest of his body. 'Wait, you can't do this, what are you giving me?'
He could see him, Death's small and quiet smile. The grim reaper was a being that stayed on the outskirts of the world, only entering it silently to take away a soul that had lost its Earthly body. A life ending was the only interaction Cas had ever seen the horseman take part in. But at that moment there was something else in Death's face, like he was happy to do what he was doing. "I'm giving you my energy, Castiel. It'll push you over the edge and you'll be a full-fledged angel, at which point I expect you to fulfill your duties."
Cas shook his head, 'No, you can't do that! You can't give yourself up for me; I haven't done anything to deserve it! I opened Hell and I have no idea how to get to Heaven, I'm hopeless-'
"Shut up. This isn't going to kill me, though I will be gone for sometime. I have seen insignificance in this world, Castiel, and you are certainly not it."
Cas fell silent and did what he could to accept the gift. A horseman of the apocalypse, a demon, and humanity had sacrificed for him to do what he was meant to. As much as it pained him to allow it, he'd be spitting in their faces if he let himself die after everything that had already happened. Castiel opened his eyes.
The knowledge of an angel was more than he'd ever expected it to be. He couldn't have previously fathomed the idea that an angel could know things about the universe, tiny, and enormous things that he'd never even thought of before. His life was in front of him and the few years he spent in it already seemed to be so small in the broader spectrum. But the way it appeared compared to everything else in the world didn't matter to him, because he knew what he'd done was important. Dean was significant, his parents were significant, Sam and Jet, Meg, and every life he'd encountered were significant. It didn't matter that he now knew how old the Earth was, or how large the universe was, or even the simplest details of the furthest past. He was still Castiel Winchester, and he knew that better than he knew anything else.
But knowledge was only a single step in living; experience was an entirely different animal. Maybe that was why he believed so strongly in himself that he was a Winchester through and through. Experience taught him more than a zap from the grim reaper – though that burst of life force did give him his full angel education.
In his mind he knew what Heaven was, he understood it on a level above a human but that didn't change the awe in his system when he saw it for the first time. He stood outside the gates with wide eyes, everything was frozen in place and it was almost as if he were watching a museum. Bodies of demons and of angels alike were strewn about the place, some dead and some mid-battle. It was incredible and it was all going to come alive in seconds. It was beautiful, he'd never seen angels before and from the distance he stood at they were just wondrous statues of power. Were they like him? Would they like him? He didn't know how different he was, he was an angel but there was something inherently different within him.
Cas knew what would happen when he opened the gates, time would slowly return to the beings around him and the battle would continue. Seeing the demons facing the angels, the pure strength given off by so many creatures, Cas wondered how Earth would fare. What about the demons rampaging there?
And where was God or Lucifer?
Castiel took a deep breath, he was ready, he could do it. This was what he was meant to do; this was why he'd been made. That concept was sad to him, as a human it felt like he was meant for more than he was as an angel. There was more to experience, more to be. But that would all have to wait, who knew, maybe he'd wind up dead and he wouldn't have to concern himself with it at all. Though that wasn't an option, he'd promised Dean.
With such a simple motion as a flick of his wrist, the gates opened. Castiel stepped over the threshold and immediately took flight. Just like Hell everything slowly came to life in a wave from where he'd entered, picking up speed and gaining on him. Cas dove through a complicated obstacle course of semi frozen beings, all just on the brink of continuing their assault.
He wished he could take in the sights around him, it was beautiful, magnificent, and more than what he'd expected. His mind had informed him what Heaven's functions were, what each level was in charge of and where human souls were left to their paradise. He knew its ins and outs, he knew where God must be and he knew the general structure of what he'd see. But again, knowing didn't do it justice. There were remarkable arches and amazing architecture that he was sure humans from old times had a hand in helping with.
His wish to see the world around him was pushed aside, however, as it had only taken moments for attacks to start flying again. Castiel's eyes glowed bright and his wings flared, he blasted through the battles leaving piles of stunned demons in his wake. Each one that touched him, an outstretched wing, or even the trail of light he left behind was slowly disintegrating. Cas didn't turn back; he didn't have time.
Larger demons were there, it had been a major attack on Heaven so obviously the biggest and more terrifying demons would have been present. Cas had been in Hell, he'd seen the torment of humankind and the monsters that lurked there, but he was still stunned. With a fully realized angelic mind he could fathom the creatures he'd seen, he knew more and understood more and he wished that hadn't been the case. Looking at one demon now was different than it had been, on a certain level it wasn't nearly as scary. But it was on many levels far more disturbing and distressing than it had ever been.
Castiel prepared himself to have to fight, his mind raced and goddamn could it race. Just because he was given all the knowledge an angel should have didn't mean he was used to it yet. He knew things that he didn't know he knew and it'd surprise him, like destroying demons moments ago with a trail of his energy. Cas was unaware he knew how to do that but it came to him like a natural reaction. Maybe autopilot would be his best bet to get him through to the highest level of Heaven but he wasn't willing to just throw his trust like that.
As he thought over his own abilities his 'autopilot' crossed streams with a demon his size. It lunged at him and he caught its bladed arm, the entire limb sharpened to a deadly point. Cas snarled and bent it, snapping it off.
"You son of a bitch!" It shouted and lashed out, each strike mirrored by Cas' limbs and it felt a little like an episode of Dragonball Z. He almost laughed at himself for thinking it.
Another angel dove in to his aid, fiery red hair and beautiful wings. Cas hadn't paid enough attention to his fellow angels; this was the first one he saw up close. 'Is that what I look like?' He could see the human form she would take as well as he true form. It was a strange mix but that was the kind of vision he had now, multiple eyes probably didn't hurt.
"Castiel, it's good to finally meet you." She said after obliterating their opponent. She could only look at him for a second before two more demons went after her. Cas beat one down with a wing and shot a bolt of light from his fingers; there was another one of those 'I can do that!?' moments.
"I'm sorry I've taken so long," he replied as he grabbed onto a third monster that joined their struggle just before it reached his comrade. As it had happened before, his brain supplied her name; Anna. "I don't know what I'm meant to do now, I've opened both gates." He trailed off and shook his head, "I opened Hell first…"
"That's alright," Anna turned and gave him a hug, "You've done beautifully, Castiel. We're all very proud to call you brother."
That was new. Cas realized what Heaven meant to an angel now; he felt a surge or pride and pain all at once from her words. He was torn apart inside for what he'd done to Earth and not being capable of going to free his family. His original family. Angels and Heaven were part of him, it was in his mind and in his system like a robot that had downloaded and installed new data. The part of him that grew up on Earth hated it, hated that he'd ever call another family his own.
But that was petty; he could love more than one group of people at a time. Earth would forever be dear to him and his family and place with the Winchesters would never leave him. However he understood more about the world than just that. The small mindedness of a teenaged boy compared to an angel that could live for eons was no contest. He was overwhelmed by Anna's kindness and felt he didn't deserve it; he hadn't earned any respect beyond just being what he was. Castiel knew he owed them; somehow he'd make it up to them.
Though his angelic family bond wasn't the only part that he owed a lot to. He would return and save Earth as soon as Heaven was able to stand up and fight with him. He swore he'd do his best to return to Dean, and if an angel's best wasn't good enough then he knew that he was never meant to exist in that world at all.
"Go on," Anna urged him and drew a sword he hadn't realized she'd had, "They're waiting for you."
Cas wasn't sure whom she meant but he could guess. He took off again, speeding through layers of Heaven. When he came across the third Heaven he saw the gates to Hell again, the ones he hadn't been able to cross when he was down there. It was open; he could feel the awfulness of Hell lurking beyond it and watched angels as he flew by. They were trying to force it closed again, demons Cas recognized from his stint in Hell attempting to burst through.
It was a split second decision but he couldn't just pass by. Castiel dove down and, in the flashiest entrance he'd ever made unintentionally, slammed into gate's doors. In his momentum he managed to crush a demon halfway through and sever its upper body. The other angels got to work on sealing it again immediately, some looking up at him in awe.
"Is that Castiel?" He heard one ask but he didn't stay and chat. The longer he was there the more Heaven woke up, and with that came the increasingly upsetting knowledge that something was wrong. The Heavenly Host was poisoned, Lucifer was somewhere inside and angel-kind was dying.
It hadn't affected him but the grace of all the others was weakening and he didn't know how to stop it. That was something only God could tell him. Cas knew he had to get higher up and find God sooner; he had to save the angels. He wished it had been as simple as he'd believed it to be the first time, that all he'd have to do was open up Heaven's gate and the angels would pour out.
But, he supposed, there was a reason behind it all sealing in the first place. It was because of the attack on Heaven, it was God's last-ditch effort to give their cure a chance; Castiel. Cas wasn't sure how but he was the last hope, not just in unsealing the afterlife but also for all of the angels. It was inside him, there was something about his grace that didn't do what all the others did.
Cas knew then that there would be no angels left if he stopped to try and save them all along the way. He had to cure the disease that was spreading through them.