My character would be a Northern Ancelstierran, and a former student of Wyverly College.  She crossed the wall some time ago and took up Necromancy out of a typical sort of morbid curiosity.  She didn't understand what it would mean for her Charter mark, and now it is corrupted, though not beyond repair.  

She wants to remove the taint of Free Magic, but keeps finding herself using it out of necessity, and is trapped in a vicious cycle, not even able to cross the wall back to her home country.