The end is where we begin

 Fandom: Supernatural

Pairing(s): Dean Winchester/Castiel

Warnings: Major Character Death

Words: 844

Summary:  Based on this tweet. Dean has a demon possessing his body, causing him to do things Dean would never want...

[Ao3 link]

"Dean."

Dean didn't reply as his eyes switched back to black. He grinned his perfeft grin, a grin only Dean Winchester could pull off. And somewhere, Cas hoped Dean was still there. It would be painful for him.

"Dean."

"Your boyfriend is gone, long long gone," the demon replied.

"I refuse to believe that," Cas said. He saw the demon's eyes flicking back to green for a fraction. Dean.

"Dean, I know you're in there, and if you can hear me, I want you to know that I am sorry and I will forgive you."

The demon grinned again. "Very, very touching. Now, any more last words before I slam this beautiful blade into your chest?" He held up an angel blade.

Cas closed his eyes and thought of Dean, the Dean he had known.

It had all started in hell, the part Dean didn't remember. When Cas laid eyes on Dean's soul, it was the purest soul he had ever seen.

Once Cas was done with putting Dean back together, he rose Dean from hell, back into his body. The work had been though and he had left a handprint.

The first time Dean had seen Cas was actually funny.

"Who are you?" Dean had asked.

"I am the one who gripped you tight and raised you from perdition"

"Yea, thanks for that," and with that, Dean had planted his knife in Castiel's chest. The surprise on his face wasn't even acted when Castiel took out the knife with ease.

They had been on bad terms for a while, Dean didn't trust Cas. But soon, he figured out Cas could help. He had become Cas' friend.

Amd even after the leviathans, even after Cas had become God and even when Cas had done such terrible mistakes, Dean had always forgiven him.

Cas had left Dean in purgatory, and when Dean found him, he smiled and hugged Cas. When Dean got out of purgatory without Cas, he'd been having visions until Cas was back.

When Cas' mind was controlled by Naomi, Dean didn't let him go. Dean told him to fight it. Dean said he needed Cas. And as had fought. And Cas had won.

All the things they had done together, the times they've helped each other, whether it were with a job or just a regular thing, they knew they could count on each other.

It was a different friendship than Cas had with Sam. They were family, he, Sam and Dean. But there was a difference between them, and Cas could not put his finger on it.

6 years, and now Dean was a demon and Cas couldn't help him. He wished he could, he would have given everything to give Dean back his body. But he couldn't.

Cas opened his eyes, noticing the demon was still waiting.

"Yes," he spoke. "I'd like to say something. Can you make sure Dean hears me?"

Suddenly, Dean's green eyes were back, full of anger and also... love.

"Dean, I want you to know something," Cas began. "I don't care what the hell that demon is gonna do, it is not your fault. I know you will blame yourself, but promise you'll fight against it.

Find Sam, he'll find a cure. You'll get through it, I promise. I forgive you."

"Cas.."

His eyes switched back to black. "Enough talking," the demon said. "Showtime."

He held his blade in the air, and right before it hit Cas in the chest, Cas thought about how ironic it was.

Dean had seen him the first time and he had stabbed him. The first and the last time Dean would see him, is when he would stab Cas in the chest.

He felt the blade slice through him, making his chest heat up like fire was in it.

He looked up one last time.

The demon had given Dean his body back, for one second. One second of pure torture, where Dean felt his own hand stab his best friend in the chest. He saw the white light coming, yet he kept staring at Cas' blue eyes.

They were as blue as the first time they met.

When the demon took over his body, but kept Dean watching Cas die, Dean couldn't do anything. He had killed Cas. He had stabbed Cas in the chest, and now Cas was dying.

Right before the white light was too bright and Dean had to look away, Cas said one more thing. The one thing Dean had always wanted to say yo Cas.

And it broke him. He shuddered as he heard Cas say the words, forming them perfectly as if he wasn't about to die in any second. He felt his heart break and let the demon take his body again. It didn't matter.

Because those words had hurt him even more than the demon ever could. It couldn't be true. Cas didn't mean it.

But he did. Dean looked at Cas' eyes as Cas spoke the words, and Dean knew Cas told the truth.

"Dean Winchester, I love you."