>>58273The "sole survivor" backstory—which is the default one unless you choose to customize your character—is that
Cobra was experimenting with controlling sandworms and ended up causing the incident on
Akuze that the rest of
Adrian(ne) Shepard's unit died in before the start of game 1.
It's handwaved away by saying "Yeah, well that was just a rogue cell that was working without authorization from the main Cobra organization" even though that and other evil science plots to kill humans is basically the only thing Cobra even did in the first game.
It's really stupid.