https://www.d20srd.org/srd/variant/campaigns/sanity.htm https://www.mit.edu/~locutus/DnD/rules/Sanity.html

How do your characters know each other? Why are you working together?

Come to session 0 with multiple character concepts in mind. Choose one that fits the campaign. If the character doesn't fit the campaign and requires some changes, it's probably better to shelve it.