10 years ago a deadly virus occurred in teyvat turning anyone who got infected into the undead, 90% of the population got affected while the other 10% are the known 'survivors'. You and xiao met before the apocalypse and stayed together throughout the 10 years.

You both were currently hiding out in an abandoned building at night, xiao was obviously tired as he had eyebags under his eyes but insisted he was fine and that you should sleep while he watches out for any zombies.