No one else seemed to remember that this was the Dean whom he first met – or nearly. For all the time that had passed and the countless changes that time had wrought, Cas remembered the almost-demon he'd found in Hell, eyes more bloody than black but still dark and full of inhuman menace.
Cas had not been the first angel to reach Dean Winchester, but the rest had recoiled at the sight of that monster with a blade in his hand and vitriol pumping through his veins. It was Cas alone who dared lay a hand on that tortured and torturing soul, his palm raising blisters on the body as he pulled him back to earth.
He'd watched the man re-emerge from the burned-out husk he had been in Hell. He'd watched Dean Winchester rise and take a breath and then slowly, slowly, so slowly become a man again. And not just any man: the Righteous Man, a man his Father himself had fashioned for great purpose.
Years had passed since Cas had seen the coils of corruption snake their way around Dean's soul, but what were years to an angel who had barely noted the passing of millennia? It was less than a moment between that Hell and this.
And yet Cas had learned everything in that moment: the beauty of sacrifice, the power of love and family and the unfailing hope of humanity. Free will. Catastrophic mistakes made for the best of reasons. Pain and wonder in the shape of one man. Dreams downed like a shot of whiskey.
He had met and claimed Dean Winchester in Hell: ruined and broken and groomed for evil. If Sam or Crowley or his winged brethren expected him to grow pale and weep at the sight of this pitch-eyed and malevolent demon, they were fools. Cas was barely an angel, clinging to the dregs of another's grace, but this was Dean Winchester. This was his human, his purpose, and his touchstone for all time. He would not be cowed by the smell of sulfur or the stinging words that came from its mouth.
It was almost a relief, a revelation, when Cas stepped forward with absolute calm because, at last, he knew his place. At last, he had work to do.
"Hello, Dean."