The animus wasn’t like that, not in this version of reality. Instead, it read your genetic history, then physically projected you into that history. Time travel.
It still required high synchronisation with your ancestor, so few subjects were able to hold a memory for longer than an instant, causing them to appear like a whisp in the air, a movement from the corner of their ancestors’ eye, but disappeared by the time they turn their head.
It was enough for Abstergo to capture fleeting images of a companion in their targeted memories. A man sometimes briefly appearing in modern clothing, but most often wearing period typically assassin gear.
So when Desmond got a license for his motorbike, their system flagged his image instantly.
They brought him in and put him in the machine, and he lived alongside his ancestors. He had to earn their trust and join their travels, desynchronising if he moved too far from them, but able to move and act independently. (This was a boon for drawing attention away from whichever ancestor he was with. He could draw enemies away until he desynchronises and disappears a safe distance from his ancestor.) But desynchronising meant being respawned with his ancestor, which could be dangerous too.
Instead of absorbing his ancestors abilities, he learned alongside them, often being taught directly by them. He could be injured, but the animus would heal him as he resynched. Even a mortal wound only caused desynchronisation and respawning. (Desmond feared what might happen if he was killed too quickly for the animus to desync and respawn him in time.)
Desmond only came out of the animus at night to eat and rest. And while in the animus, from his perspective, days, weeks, even months would pass as if he was experiencing every moment. All that data couldn’t be viewed in real time for those monitoring the animus, so only those moments they were interested in were slowed down and played on their screens, only those moments were saved in their system.
But Desmond lived with them.
