Blessed with Suck: Arithon possesses the gifts of foresight and empathy, meaning he can foresee every consequence of every action he takes, and feel the suffering these choices will cause.
Cool Sword: If Alithiel were any more awesome, it might as well be a lightsaber.
Casting a Shadow: Type 2. Though there's brief speculation that it may be something more than that...
Dark is Not Evil: Arithon, the Master of Shadows, is actually a pretty decent guy, but his gifted geas of empathy makes it hard for him to be around people.
Death Seeker: To the point that the Fellowship binds him against committing suicide to prevent further suffering from his half-brother trying to get at him.
Doom Magnet: Arithon tends to leave a trail of orphaned, dead, and imprisoned comrades in his wake, because his half-brother, driven insane by his cursed geas, can't get at him, and therefore lashes out at those closest to him.
Guile Hero: Arithon seems to love pulling off plans of many kinds. Most notable are his plans counting on Dakar's attempts to sabotage them in Ships of Merior, and in Traitor's Knot, both his original plot to discredit Lysaer's campaign by harmlessly humiliating the sunwheel priests and, later, his method of infiltrating the Kralovir by setting up a complex chain of events that could have been toppled at any moment by the slightest mishap. Not to mention damaging the Great Waystone by turning Prime Selidie's tracking sigil for iyats against her, knowing she wouldn't be able to resist spying on him again.
Heroic Bastard: A strange case here. Both his parents were royals - they just happened not to be married to each other at the time he was conceived. Also, since he is the last surviving s'Ffalenn, he is inheritor by default.
It's Not You, It's My Enemies: Arithon knows that Lysaer has all the resources of the Rathain merchants, including a sizable army, at his disposal, and no compunction against harming anyone harboring Arithon. Therefore, he has to keep moving and avoid getting too close to people in order to minimize the effects of his Doom Magnet status.
Magic Music: He's pulled some truly amazing stunts with his lyranthe and, in some cases, just his voice or mind alone.
In Ships of Merior, he quite accidentally awakens the Fifth lane power circle under the Mayor's hall in Jaelot while playing Halliron's eulogy, effectively destroying most of the city. Few are hurt, but Jaelot's citizens are not pleased.
Peril's Gate: Arithon used his Masterbard's ear and lyranthe to play the Paravian songs and awaken a dormant power focus in Sanpashir.
Reluctant Ruler: Arithon would rather do right by the common people of Rathain than be big and important.
Samaritan Syndrome: Arithon can't appreciate the privileges of being prince of Rathain because he feels too acutely the suffering of the poor and oppressed.
Technical Pacifist: Due to his gift of empathy, Arithon doesn't want to hurt anyone - just don't push him too far...
Abusive Parents: Lysaer's dad was a dick to his mom, and wanted to use Lysaer's gifts against the s'Ffalenns. Considering that said mother is shared by both half-brothers, we can figure out how well that went...
Kick the Dog: Lysaer has a few moments shortly after his exorcism to show how his character has changed. In one case, he literally kicks a dog that had snapped at his heels, without even a thought regarding how out of character it would usually be for him. Earlier that day he had smashed Arithon's lyranthe in a fit of rage.
Knight Templar: Lysaer, whose gifted geas of justice was twisted and corrupted by the Mistwraith.
Body Double / Doppelgänger: Turned a bit sideways on both counts. Fionn was magically altered by Lirenda at birth to resemble Arithon, in order to use him as a tool to draw the original out by threatening to have Fionn killed in his place.
Seeker Archetype: He set out to find where the Paravians had gone, and hasn't been seen since.
Davien the Betrayer
Evil Sorcerer: According to popular belief due to his unspecified role in overthrowing the High Kings. However, given the nature of the series and hints dropped so far, it's implied that his motivations were anything but evil, although exactly what they were is still unclear.
The Ghost: Davien is mentioned many times but never seen. The effects of his shenanigans are, however.
He makes his first (brief) appearance in Grand Conspiracy, though, and plays a major role thereafter.
Foil: To Luhaine. Kharadmon is tall and lean when manifested, preferring to move through air and tending to be irreverent and free-spirited, prone to quick, impetuous action and snark; Luhaine is short, portly, prefers moving through the earth and leans toward fussy perfectionism and stuffiness with a propensity to lecture. Yet they work well together, even if they don't always appear to get along.
Ascended Fanboy: Jieret is willing to follow Arithon into battle to prove his worth, even if his parents forbid it due to his young age. When his father dies during the battle of Strakewood Forest, Jieret inherits the title of Clan Lord.
Domestic Abuser: He wanted to use his wife's dowry as a weapon against the s'Falenn, and was prepared to rape her to get a second child with Lysaer's elemental mastery. In a vision, he is seen beating her when she refuses to agree to go along with his grudge.
Kill 'em All: He sent every man, woman, and child suspected of sorcery or of harboring his wayward wife, Lady Talera, to the execution block.
Rebellious Princess: Not against her family, mind you, but she isn't satisfied to stay behind while Lysaer gathers his army, and jumps at the chance to go with Pesquil to deliver news on Arithon's location.