The Tale of the Five/Characters

Blessed with Suck: The blue Fire, if used, shortens the life. Sorcery just gives backlash -- proportional exhaustion.
Blue Oni: to Freelorn's Red Oni; Herewiss is the calm, planned, organized one who is more introverted and, inside, wound rather tight.

Ermine Cape Effect: young Freelorn dressed the part and made damn sure everyone knew he was the crown prince of Arlen. Later on, he grows out of this a bit, but he still likes the royal trappings at times.
Fisher King: by the Royal magics, the rulers of Arlen and Darthen are bound to the lands they rule (as are lesser Lords). In times of famine, rulers have been sacrificed for fertility in the past.
King Incognito: at times during his wanderings, and also when stealthily entering Arlen in book 3, looking for his Initiation.
Red Oni: The counterpart to Herewiss's Blue Oni, Freelorn is the passionate, fiery, leonine one (he's "the Lion" after all).
Rightful King Returns: Freelorn's journey, and the especial focus of Book 3, The Door Into Sunset, which is "Freelorn's Book"
Royal Blood: The royal magics which bind the Shadow and secure the land are tied to the ruling blood in both countries.
Royals Who Actually Do Something: being King of Arlen isn't exactly easy, which is why Freelorn runs away from the responsibility for so long.

Absurdly Sharp Blade: Skadhwë, the splinter of Death's door.
Be Careful What You Wish For: Segnbora wishes to be changed, in desperation and despair of ever reaching her potential. She gets a change a whole order of magnitude greater than she could have imagined.
Blessed with Suck: Both the blue fire, the use of which shortens the life, and (for a while at least) the dragons.
Half-Human Hybrid: She becomes this, pretty much.
Meaningful Name: Segnbora, in old Darthene, means "Standard-Bearer", and she locates Freelorn's Lion standard and carries it into battle in Door into Sunset.
A Mind Is a Terrible Thing to Read: Segnbora's Underhearing is so sensitive that she constantly hears more than she really wants to.
Rape as Backstory: The secret she tells nobody, until Hasai comes along.

Modest Royalty: Eftgan is normally working way too hard for that.
Royals Who Actually Do Something: being Queen of Darthen is hard work, and sometimes dirty work.