The pieces are starting to fit now. Elanna was obviously an operative from the Thracian Assassin's Guild, and a deeply entrenched spy. She must have infiltrated Bastone as a noble's ward, then made her way to Verum under your protection. Once here, she most likely set out gathering information about the city's defenses and the palace's weaknesses, with it all culminating in your confrontation today. You may not yet know who she was sent to kill, but her Guild is known only to deal in 'high value targets'.

However, that must all wait for the time being. There are more pressing matters you must deal with immediately, namely bringing order to the city and finding witches for The Keening.