Meaningful Name: Lavan means "white" in Hebrew. Here both literally meaningful (he's a Herald, and so wears white), and figuratively so (he's basically a naive kid who ends up channeling forces he doesn't understand and can barely control).
Mindlink Mates: An interesting example in that Lavan is both life and Companion bonded to Kalira. The double bond is necessary for controlling his Gift but means that he is almost completely dependent on her.
Morality Chain: Kalira. In this case, it isn't that Lavan would turn evil without her, but he would quickly go insane. The Karsites find this out firsthand.
Lan going evil is hinted at. Because his power is fueled by anger and the Karsite war is so terrible, by the end he's fallen into a bad habit of getting wrapped up in his anger and rage with Kalira being more and more ineffective at reining him in.
Person of Mass Destruction: Lavan is a living weapon capable of annihilating entire armies. He receives special honors, consideration and protection because this ability made him into Valdemar's WMD at just the right time to repel a Karsite invasion.
Cannot Tell a Lie: To the point that Lavan notes that it's like Tuck has a permanent Truth Spell on him.
Real Men Wear Pink: He learned how to sew from his grandmother, and as a consequence, one of his chore duties at the Collegium is in the mending room. He greatly enjoys the fact that he is the 'only rooster in the henhouse'.