Once your Destruction skill reaches 100, a new conversation option ('What else is there to be learned about Destruction magic?') opens up with Faralda, the Destruction trainer at the College of Winterhold.
Visit North Skybound Watch, same as before, but casting a frost spell.Visit Windward Ruins, activate the pedestal and cast a fire spell on it.Talk to Faralda, who will give you a book.Uncover the secrets of the Power of the Elements
