Offset Determination - (Fem!SS!Chara x Any!Reader) [PACIFIST]

(Just by looking at the thumbnail, you can tell what this is gonna be about.
Warning: This is my FIRST xReader, so bear with me here. Also, the Any! means Any Gender.)

Quite a long time ago, MONSTERS were sealed Underground by seven powerful HUMAN mages, each with a different type of SOUL. This seal, or Barrier, can only be broken with seven HUMAN SOULs. They must be of the several different SOUL TRAITS. Patience, Bravery, Integrity, Perseverance, Kindness, Justice, and Determination. The King of Monsters, Sans, has acquired six of the seven SOULS needed.
That's where you come in. Will you MERCY you way to Der Skelettkonig?
Or will you kill everyone in you path?

That path you choose... Will determine how the story ends.
[There will be two books, [PACIFIST] and [GENOCIDE]. Depending on which ending you want, you can freely switch between books. There won't be much difference!]

[i'm gonna write this one first, then do genocide after this one's done.]