You can teleport to the shrine outside on Sentinel Island, jump up the nearby rocks and run over to where there are no overhanging tree branches in order to change into a dragon (IIRC you may also be able to find a spot on the path down to transform, or jump off and turn into a dragon before you get too deep into the poison gas). There are probably a few remaining attackers, left when you automatically returned to the battle tower, as well as a few places you can now reach as a dragon, and you will be able to transform near Michael's raft. The quest to retrieve a book from a boat in a tree can also be done now, but you might want to consider using the book yourself, rather than complete the quest.
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