A/N: So, in this au, Chara and Frisk are both girls and Kris is a boy and this would be taking place shortly after Undertale. Carter is a 17 year old 3rd year high schooler and one of Asriel's three adoptive siblings, the other two being the ambassador of monsterkind, Frisk and the late first fallen human, Chara. Three weeks later after Toriel adopted Carter, a looming threat to both mankind and monsterkind is born. Now, the two species both works together to stop it, but will their combined efforts be enough?