Who is Syl in the novel, The Way of Kings?

Syl, or Sylphrena, is a windspren who becomes very attached to Kaladin. Throughout the novel she gains a consciousness other spren do not posses and she increasingly acts as Kaladin's conscience. She is attracted to Kaladin's swift movements in battle and his devotion to honor. Later, she remembers that she is a bindspren/honorspren and she is attracted by oaths and honor.