Nothing could ever compare to the panic of knowing it was the last time he would see his brother. But it wasn't only that. It wasn't only horror… it was a heartrending sorrow too.
Powerless. Right in that moment he hated his powerless self more than ever. Ragna said he had grown strong, but then why was Jin on his knees, defeated? About to face the worst tragedy that could occur to him? What was the use of gaining such strength, of having learned and overcome so much, if he couldn't win when he needed it the most?
"I can still fight" he had stated, desperately, but Ragna's answer was nothing but the promise of the impending end of it all. Of everything that Jin wished for. The world would be saved, but Jin's world was crumbling irreparably.
When he clung to his brother, he was no longer attempting to change anything, not quite resigned… because he'd never be able to, but utterly overwhelmed by heartbreak. And he was crying, like he hadn't cried in years. The tears streamed down his face without giving Jin any chance to hold them back, no, he just couldn't. He couldn't speak, he couldn't think, he could barely listen.
He never had high hopes. He knew life would never be 'normal', would never be particularly kind, but no matter what horrible things happened, Jin did held on to a promise, one that motivated him to become stronger and keep fighting for a long time. But that promise was dead now, and instead he was left with the promise of oblivion.
It was like drinking poison… the torture of being granted a few moments to face the pain and horror before everything went dark forever. Jin might not be facing death, but being forced to forget seemed even crueler. Dying alongside his brother would have been the most merciful way to end the story, but he wouldn't be granted that, only to be abandoned instead not only by Ragna himself but also by each and every memory of him.
He wished he could say he would regret it forever if the last glance he had of his brother was blurred by his tears, but he knew he wouldn't even have that memory to regret over. Still he forced himself to stop the tears, and looked up at Ragna, hands holding on for dear life to that red jacket, and he saw him smile… God, he loved him. How painstakingly tragic. But that's how most things had been from the start anyway, and yet this was without a doubt the most unbearable.
But how dare Ragna smile? Silly nii-san, probably thinking he's making things better by showing such an expression to Jin before leaving him forever. It's not any better, it can't be.
At least, Jin is more or less sure he managed to exchange a few I love you's with him before Ragna's final words to him reached his ears. Nevertheless, his consciousness is already drifting by then, against his will, into blackness. His field of view became narrower and narrower, but even then he took in the sight before him, Ragna, becoming blurry and distant with every passing second. With the last of his consciousness Jin realized that it wasn't only his senses shutting down, but every single imprint in his mind related to his beloved brother being ripped and shattered to the last trace. This really was… the last time. A red blur was the last thing he saw before it all went dark.
Oblivion would never be a proper consolation, but it might keep him alive, he knew. All possible sense of fulfillment might go along with his memories, but the world he lived in had been saved. And so life went on, with a melancholy that Jin was never able to trace back to it's source, it just seeped into his soul as if it was an innate trait of his very existence, just like the many voids in his memory and the incessant longing for something he couldn't name.