Sisters in Sin

A demon of lust walks into a monastery wearing a preacher's collar, and nobody thinks to check his references. Playing the disguise straight, you rearrange schedules and duties to get close to the sisters, learning what each one is hiding under the habit before you go to work on it.

The setup is simple corruption-by-proximity: control who prays where, who cleans what, who's alone with whom, and let opportunity do the rest of the persuading. Vows bend under enough patience, and the monastery slowly stops looking so holy. Multiple endings mean the ruin you build is yours to shape, not a fixed script you're clicking through.