itsBrianna-
Sigmund John Fox created another personality called Klauz De Franz because he felt worthless and alone. Klauz helped him feel more confident, but later he started to become the more dominant personality.
The doctors diagnosed him as a BPD, someone with Borderline Personality Disorder. None of Sigmund's classmates understand his disease so they just make fun of him, make him feel out of place, and Sigmund has no one at school, until the Fat Kid, who later introduces himself as Julio, helps him learn how to have fun.