It takes fifteen years for Reaper to realize he's not aging.
Well, no, that's not quite true; he had suspected before. He may have traded a microscope for a sniper scope, but he'd been his team's medic in the RRTS, and he's absorbed enough medical know-how to realize what it means when a body stops accumulating cellular damage.
He hadn't wanted to think about it, though; had deliberately ignored it until the day Sam makes a joke over the phone about her blonde hair camouflaging the grey and he realizes that his is still as dark at forty three as it had been at twenty. He spends a long time standing in front of the mirror that day, checking for crow's feet and smile lines and all the other wear a man's face accumulates with the years.
He doesn't find any. Two days later, John Grimm resigns his job and assembles a new identity.
It takes another fifteen years for Reaper to discover that he's not alone.
His sister is nearly sixty by then; he drifts by every few months to let her know he's still kicking, and she introduces him to every new family member as 'a cousin from my brother's side.' Her older kids know the truth, but they also know why it's secret; and as the years have passed they've deliberately begun to treat him as though he really is one of their generation. Building ties for when his sister leaves him, he assumes-- he knows she knows that he knows that's what they're doing, but it's easier to let her believe it'll help than to fight them.
That's how he meets her: out at the bar with his sister's youngest and their friends, knocking back a beer or three that barely affect his metabolism. She's dressed in jewel-toned club clothes, synthetic leather trousers with a low-cut silken shirt and emerald streaks in her hair; she looks maybe twenty-one, far too young to even think about taking up on the extra beer she orders from the bartender, but something in the depths of her vivid blue eyes compels him to accept anyway.
She introduces herself as Aurora, and captures his attention effortlessly with the tenor of her laugh. It's-- wry, a little self-deprecating, distant rather than joyful; and over the course of their first conversation he has the pleasure of watching her attention sharpen on him in turn. Something in her resonates with him, and she senses it, too. Sincerity, maybe? A surety in themselves that the tweens around them have yet to learn? A predator's patience, and the sense to know when to seize the moment.
They spend that night together. And then another-- and several more--
--And then she hears him call grey-haired, grandmotherly Samantha 'sister' on the vidphone, when she cuts a shower short to emerge from his bathroom wrapped in a towel.
She studies him a moment, thoughtfully, but doesn't ask. Instead, she takes a book of old-fashioned paper photographs from her suitcase. Seventy years' worth of memories lie between its covers: seventy years of her grinning out of the album at her own aging's sister's side with the same face she's shown him today.
Something off in her genetic make-up, she explains: a freak mutation.
Something in his genetic make-up, he confirms: returning trust for trust.
And as she trembles against him later that night, he knows his sister was right all along. Despite his determination to carry the burdens of his unwanted immortality alone, the moment Dawn 'Aurora' Summers held out her hand, John 'Reaper' Grimm had finally found his anchor.