You got a book of magic that can control wind when you rescued the guy on the top of the pillar (near the trainer Kenneth). There is a windy spot near where you start on the island with a tombstone and three candles...
I don't recall having to go back to the cave the necromancers were in. After you do the quest referred to above you get access to a cave by the sea side shrine, near where Allan is/was.
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