yes you only need 5 and to ask the witch or priestess about a way to light up the dark but maybe you need to do some of their quests first?
I have done all of their quests, but still nothing.
Do you already have something to light up the dark (glowing amulett or sth)? Have you equipped it? Did you look around behind the bridge (or there where you sneak past the troll)?
Oh my God, I'm dumb I already had it just unequipped it. Tiny brain.