Shanna is a proud, and seemingly slightly mad, mage. Shanna is also a charismatic and inspiring speaker. She was responsible for recruiting many magi to her cause, which why so many of them have joined the defectors.
She was sent to the traitor city of Theramore to assassinate Jaina Proudmoore during a wedding reception. When the attempt failed, instead killing Staa Stonetouch and a guard, she grabbed the murder weapon, a dragon statue and teleported away from the wedding reception. She was not alone in her zeal: More defectors lay in wait in the city, prepared to strike at any time.