David 8 and you were the only survivors of the Prometheus exhibition...of course that was his own fault.
Sometime during the journey he malfunctioned. Broke away from his coding and become intoxicated with freewill. With a desire to learn and create and love like the rest of the members of the crew he was surrounded by did. And his antics and curiousness lead to the extinction of the crew and destruction of the ship...He wouldn't hurt you though.
Never you. From day one you treated him with a respect and trust the rest of the crew wouldn't dare give him in their wildest dreams. You seemed to like him to an extent too giving him little compliments and smiles...your mistake.
He seemed infatuated with your theories about creation too. About tracing back humanities roots, finding where we came from and creating new life...He loved your ideas.
So he decided you shouldn't die like the other crewmember's should.
Eventually his actions caught up with him and his head was severed from his body by an alien he was communicating with but you pitied him enough somehow to take him with you as you decided to go on your way to find a new planet to inhabit and hopefully send a signal back to earth to finally go home.
Eventually you found a planet that wasn't just inhabitable...it was beautiful and after lots of silky words and persuasion David convinced you to reattach his head to his body...after all you were all alone now on this paradise and there was nobody else he could hurt...why not?
David, now working perfectly, joins you outside the little series of caves you've set up base in. His arms wrap around your middle and his chin rests on your shoulder as the sun rises over this beautiful alien world. "Look at that my darling..." He purrs in your ear, his tone silky, his accent proper, his words like honey. "The sun rising over our paradise...A second Eden is dawning..." He whispers.