Important Haircut: Part of giving the oath to become Swordsworn; the cut hair indicates that the oath has been accepted (The oath is traditionally performed in a place with no sharp objects in it and made without any blades on one's person, so it isn't possible for the oathtaker to cut his/her hair unless the oath is accepted). She repeats it in The Oathbound as part of her ritual preparations to face Trial by Combat as Lady Myria's champion.
Spirit Advisor: Swordsworn are taught by the spirits of past Swordsworn; several of Tarma's "teachers" appear throughout her books, and she herself is implied to have joined their number by The Mage Winds, in which a spirit-Swordsworn calls Elspeth "student of my student."
In Storm Breaking, a spirit-Swordsworn talking to Karal mentions that Kerowyn is the spirit's kinswoman. It's not proven to be Tarma, but it's certainly suspicious.
Tomboy and Girly Girl: The tomboy to Kethry's girly girl. Though amusingly, she's far better with children than Kethry is.
Lady Kethryveris "Kethry" of House Pheregul
Blessed with Suck: Her magic sword Need may grant her absolute mastery and heal any wound, but it also forces her to come to the aid of any woman in need (hence the name). It wasn't a big problem until Leslac publicized it and they had to rescue so many women (for free!) that they didn't have time for paying work.
Heroic Suicide: He drugs himself asleep during the trip through the mountains into Valdemar, intending to let himself die of cold rather than continue to burden Tarma and Kethry if they can't find sufficient shelter. Fortunately, Roald shows up in time to keep it from being an issue.
Modest Royalty: He claims he's just another Herald and "not that important" so long as his parents are still alive and ruling.
You Didn't Ask: He doesn't really do anything to hide the fact that he's the heir to the throne of Valdemar, but no one actually sees fit to mention it until Kethry challenges his ability to make good on his promises.
Abhorrent Admirer: Tarma and Kethry get tired of his attentions fairly quickly, especially after they realize he's making it harder for them to make a living. Ironically, there's even a song about it: "There's Always a Reason (A Curse Upon All Bards)" Tarma finds him exceptionally trying, since he persists under the delusion he can defrost the ice queen by singing "That song" under her window.
Cursed with Awesome (if only from Tarma and Kethry's viewpoint): his songs are "true in the main, if wrong in the details" and make them out to be heroes. Unfortunately, they're also catchy, so now everyone expects them to work for free.
Defrosting Ice Queen: Leslac's hopes for Tarma as spelled out in the song "The Swordlady, Or: 'That Song'". He's wrong, of course; doesn't stop him from trying.
Shotgun Wedding: Tarma eventually bribes Stefanson to arrange one for him to get the man to leave her alone.
Unreliable Narrator: He is determined to turn his tales of Tarma and Kethry into heroic epics worthy of his talent — whatever it takes — despite the dubious nature of some of the actual events that inspired them. Amusingly, the most inaccurate of his songs about their deeds was about one that he actually witnessed — he couldn't bring himself to write a song about how Tarma hit a belligerent drunk (who happened to be a highly unpopular local nobleman) with a broom, resulting in him accidentally hitting the fireplace with his head and dying, so he wrote a song about how she heard about Viden's evil overlord, called him out, and cut him down in an epic duel instead.