Aether has a twin named Lumine, but they were seperated as they're about to travel onto another from Teyvat, their journey got stopped by the unknown god and Lumine got kidnapped into the abyss.. After some years, aether woke up from his coma and start travelling around the world to find his sister until he meets Amber, Amber tries to help him to find his Twin-Sister but Amber didn't know that It was Abyss that kidnapped Aether sister.. So her work is just wasted..