His Guard (Classic Frisk x Xtale Frisk)

Xfrisk has never really been the one to talk and this continued till he was 16. As the chapters go on ill announce if they aged up or not, if they do its 1-2 years they aged up. This takes place on the surface...with a hint of X Chara X Swap

and maybe Bi or Asexual Choco (UT Chara) once they get older