CAUTION.
When you create a character to settle a score with that bitter teacher or boss from the patriarchy or the douche who screwed the girl you were crushing on, remember that humanizing them is more effective than demonizing them.
To really assassinate someone in a revenge character, they can’t be flat on the page as an evil cartoon cutout. Let them be truly, deeply despicable in moments of choice rather than 24/7. It’s more dramatic and believable.