Lost tale( an undertale au)

found art on google; credit to owners of the art in this book( its really good) :)

It has been 3 years since Frisks last genocide route with Chara and she regrets everything.
Frisk wants to try to complete a pacifist rout to try to make up for her mistakes. Chara respects this decision and becomes a bad thought that sometimes gives useful advise in the back of frisk's mind.
Frisk finally resets but there is something different with this time line. Sans remembers everything. He hates frisk down to his non existent gut, until the "fight" with papyrus...

Maybe lemons

potential ships
frans (frisk x sans)
Alphys and undyne