Wat Gordon
- Action Hero
- Contrasting Sequel Main Character: To the much more even-tempered Will in Men of the Moss Hags.
- Hero with Bad Publicity: So much. A combination of bad luck, his own pride and impetuosity, and Barra's machinations manages to make everything he does appear in the worst possible light.
- Historical Character's Fictional Relative: The Gordons of Earlstoun, including Will, were a real family. Wat is their fictional cousin. (Lochinvar was a Gordon holding but belonged to Lord Kenmure, not an independent laird.)
- Hot-Blooded: He's very passionate and impulsive.
- Plot Armor: Lampshaded. "Wat Gordon of Lochinvar was not drowned - it is hardly necessary to say so much."
Kate McGhie
- Damsel in Distress: Becomes this when she is kidnapped.
- Vague Age: In Men of the Moss Hags she was older than Maisie, which combined with the time elapsed makes her around thirty by the time she faces an Arranged Marriage - old indeed for the seventeenth century, but the narrative ignores this.
Marie
- Action Girl: She turns out to be surprisingly handy with knives and guns.
- Beware the Nice Ones: She's very sweet but stabs Barra without hesitation and is unfazed when she thinks she has killed him.
- Everyone Looks Sexier if French: Though she's actually a Walloon.
- Hidden Depths: Nobody suspects her Action Girl skills.
- No Last Name Given: She's only ever The Little Marie.
Murdo McAlister, Earl of Barra
- Contrasting Sequel Antagonist: The closest thing to a main antagonist in Men of the Moss Hags was Claverhouse, whose depiction verged on Noble Demon, and who shows up as a sympathetic character in Lochinvar; Barra is far more horrible.
- Double Reverse Quadruple Agent: He's a Scottish subject who serves with a regiment of political exiles in the army of the King's rival William of Orange. He's secretly passing information back to King James, who believes him to be a Fake Defector, but he's also planning to profit from his closeness to William if James is successfully overthrown - gaining favour from each side by betraying the other - and indeed does so.
- He is ultimately exposed and dismissed by William, but returns to the service of James, who still thinks him loyal.
- Faux Affably Evil: Barra is a smooth-talking Manipulative Bastard and usually polite, but underneath it he's spiteful, petty, and cruel.
- Manipulative Bastard: An effortlessly persuasive liar and constantly scheming.
- Villain with Good Publicity: He has the ear of the Prince and can talk at least some of Wat's dearest friends into believing him over Wat.
- Villainous Valour: Informed Attribute. Barra may be vile but we're assured he's no coward.
Jack Scarlett
- The Ace: He's built up as this.
- Awesome McCoolname: Captain Jack Scarlett.
- The Casanova: It turns out he was quite the ladies' man in his younger days.
- Defector from Decadence: He quits his original service when he realises the company he's been keeping, and joins the Covenant regiment alongside Wat and Will.
- Everyone Has Standards: He is quite prepared to kill a former friend to secure the papers he was sent for - as long as it's in a fair fight. The idea of cheating disgusts him.
- Fish out of Water: Jack is formidable on land, but at sea he's, well, all at sea.
- Master Swordsman: Famed In-Story for this.
- Older Sidekick: To Wat.