I don't know why I wrote this...after I saw a post on Tumblr (I don't know where it is now but if someone's really curious and messages me I'll check) about the Doctor and Cas being a lot alike now, the plot bunny wouldn't go away :/ But oh well, enjoy! (PS This is set a few months after the season 8 finale in SPN and just before Ten regenerates in Doctor Who)

"Hello Castiel...No longer human I see." The Doctor said with a small smile.

"No…the Winchesters helped me salvage my Grace…" Castiel answered, avoiding the Doctor's eyes as he looked out into the misty lake before them.

It was quiet, and any humans in the area were asleep thankfully. No one witnessed two beings that were never supposed to meet, but were somehow friends, see each other once again.

"How? You seemed pretty hopeless when I saw you last."

"The Winchesters and I were able to track down and subdue Metatron, with the help of some. We were able to obtain my Grace and restore it thankfully." Castiel explained, still not meeting the alien's gaze.

"Were the other angels so lucky?" the Doctor asked, concern lining his brow.

"No."

In that word an entire world was born, one which the Doctor wanted to discover. He knew the trek would be painful and depressing, but that didn't stop him. After all, Castiel was his friend.

"I'm sorry." he whispered, sympathy heavy in his tone.

"Why?" Castiel asked, for the first time meeting the Doctor's gaze. And boy, what a gaze. One full of sorrow, of mourning, of guilt...but love and contentment could also be seen. He had thankfully reached a point in his life that took the Doctor a while to reach.

"Because...I know what it is like to be the last of my kind."

Cas took a sharp inhale and looked away, and his fists clenched beside him.

"Cas..."

"Do not speak of it Doctor. You were not there, you have no right."

"I have every right; after all, I did the exact bloody thing!"

"You are not to blame...You did what you needed to do. I however-"

"Did what you needed to." the Doctor said with a roll of his eyes.

"I did not! My brothers and sisters had no need to fall, to die, all for my precious conscience!" Cas hissed, self-loathing evident in his tone, "I should have done my penance, should have let myself deal with the guilt and pain. But I stupidly and selflishly needed to do good, to right my wrongs...if I had let well enough alone..."

He didn't finish his sentence. But the Doctor heard the words he didn't say; this is all my fault...everything would have been okay if I hadn't meddled...I was stupid and needed forgiveness, and my selflishness brought Heaven down along with its inhabitors...I am at fault and I hate myself for it...

He wasn't going to let Cassie feel this way was he?

"Castiel...it is not your fault." the alien enunciated, trying to catch the angel's eyes. He refused to give in and look however...but the Doctor was stubborn, so he kept on, moving this way and that. He needed his friend to understand.

"Your intentions were good. As much as you wanted the guilt to go away, you wanted to right your wrongs more...and that my friend is anything but selfish. And now, you and the Winchesters will try your best balance things out. You will, in the end. I know it."

Castiel breathed deeply into his gut and for the first time the Doctor witnessed wetness grow in his eyes. The angel tried his best to stop them, but seemingly couldn't.

"Blasted emotions! As if being human wasn't enough." he sniffled, not moving to wipe them away. Good; he learnt emotions were better felt instead of bottled. Another thing it took the Doctor awhile to learn.

"They're good. It might not feel like it, but they are. You and your siblings will be better with them when this is all over."

Castiel froze at the mention of his brothers and sisters, and the Doctor suddenly wished he hadn't said a word.

"You're right Doctor...I am like you." he continued on despite the Doctor's pitying look, "I am alone now. I am the last of my kind. Metatron is dead; I killed him. As I killed many of my brothers and sisters. That's what I shall be known for, as are you. 'The Oncoming Storm'. But Doctor, there is one large difference between us."

The Doctor frowned but didn't say a word in response. His eyes urged the angel on, but also insisted on proceeding with caution.

"I will do everything in my power to restore the balance and fix what I've done."

The Doctor froze and his eyes narrowed. For the first time Castiel saw the cold alien that let his entire species crumble at his feet.

The angel assumed that fear should be coursing through his veins; adrenaline should have been released and his body should have been shaking, ready to run. Nothing of the sort happened however. Just silent strength and a painful admittance.

"I am going to restore Grace in the Fallen and I shall balance Heaven and Earth. My brothers and sisters...They have done no wrong; all they did was try to bring God's Truth to all. They deserve to be saved and I'm the only one who can grip them tight and raise them from Earth. I have no choice...I will even die trying if I have to." Castiel said strongly, his voice unwavering as he stared the alien down.

The Doctor took the challenge and stared right back as he cried, "That's madness Castiel!"

"Is it? Is it wrong to try and help those I've wronged?"

"It is! This can be a new beginning for your kind! This can be a new beginning for everyone, no matter if they come from Earth or Hell. Find a way to close the Gates of Hell, and then everyone can live in peace without the mind games of mad leaders! Everyone can finally have Free Will! Wasn't that what you wanted from the beginning?" The Doctor asked, his arms making grand gestures as he spoke. Passion was pooling in his eyes and for a second Cas believed this all to be true. That it could be that easy. That he could settle with ex-angels and ex-demons on Earth, readjusting and equalling themselves, until only peace remained. The Doctor made it sound so simple and so heavenly...

But then the weight on his shoulders that only got heavier with every passing year reminded him of its presence.

"No, I can't...the guilt...they are innocent. And we both protect and save the innocent, do we not?"

The Doctor's face froze and his eyes dimmed slightly, losing some of the fight within him at those words. But he was quick to regroup, replying in rapid fire, "They are innocent, yes. They should've never been brought into this little game between you all. But as innocent as they may be, the humans are twice as such. And by keeping the angels human and turning the demons, you protect the human race. Just like the Winchesters had always wanted."

"You don't understand!" Cas growled, "There are many reasons this could never work; The angels-I've seen the Fallen. I've talked with many. And you have no idea of their condition, or you would be supporting me! This is not a life for them! Also, if we do damn the demons to a human existence, Sam's life would be sacrificed! I cannot do that to the boy who deserves so much better, or to Dean who would die without him."

"Castiel..." the Doctor with a look in his eyes, a broken and defeated look. A look that said, What are the lives of two compared to seven billion?

"No, I cannot do that. I absolutely refuse. I would rather die. Just as you would with for your companions, what you have done time and time again."

Castiel had him, and the Doctor knew it. He couldn't argue as his gaze dropped to the ground and his shoulders slumped. Cas nodded gently and began to turn away, knowing their conversation and their unsettling reunion was over. But before he could fly away, a quiet voice bidded him to wait. He turned around to see the Doctor with a look he had never seen grace his face; sadness. A great and terrible sadness. Sorrow built up upon the foundation of a too-long life. And this look made Castiel stop in his tracks.

"We are alike Castiel," the man whispered, his body trembling as he righted himself, "Too much so. But we are different in some ways...you have a family to return to at the end of the day. And if you die...So please...just be careful."

Castiel nodded, his gruff voice whispering, "You as well," before flying into the night. Leaving the old Time Lord to his cruel fate.