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I have to collect a quest from a follower named Yarna, beige fox.
I can see him/her from the follower's list but I can't find him anywhere, he's not on campus, he is not at sermons, he is not a missionary...
check your mines and the corners of your village. Sometimes followers just wander off in random directions for some reason. Alternatively they should go to sleep when its night, so you could wait for that to happen.