The patriarch of the family. Originally started out as Sir Graham, the son of one of Daventry's knights, but a Succession Crisis caused King Edward to offer him the crown after he proved his loyalty and cleverness in a quest. As a result, while Graham is wise and just in terms of actual ruling, when it comes to courtly manners he's a bit of a bumpkin who's still more at home acting like a humble squire than a blue-blooded aristocrat. Protagonist of KQ1, KQ2, and KQ5.
Benevolent Boss: By way of Nice to the Entire Castle Staff and his Subjects. Aside from his being genuinely nice and caring, he also reasons pragmatically that remembering birthdays and anniversaries and giving presents and good treatment and other niceties is a small price to pay for staff who are thus more motivated to do their jobs well and make his life easier.
Genius Bruiser: Though not really a stereotypical genius, per se, he does combine being "built like a linebacker" (as he's often described) with a clever, well-educated mind and preferring to think his way through problems. Though he does engage in swordplay (and frying pan-wielding) on occasion, especially in the Fan Remakes, Fan Sequels, and Tie-In Novels.
No Hero to His Valet: His Prime Minister is less likely to overlook Graham's quirks and occasional lapses in judgment, and calls him out on them now and again. Graham doesn't mind, as he feels "A king needs 'nay' sayers more than he needs 'yea' sayers."
The daughter of a prince and a farmgirl, who was imprisoned in a tower by an evil witch and eventually rescued by Graham. As a result of her noble background, she tends to be more poised and cultured than her husband, and helps him run the castle and navigate around royal customs. Somewhat more sedate and homebody than the rest of the family, though when Rosella is lost at one point she proves to be a competent adventurer regardless while searching for her. Shares the role of protagonist of KQ7 with her daughter Rosella.
Women Are Wiser: In the same novel, the fairies give her special treatment over Graham because they consider her more down to earth than her husband. She also handles social matters more adeptly.
The female half of the Royal Twins, and the one who actually got to be raised by her parents. Tends to take after her father in personality and her mother in looks. While she generally is well-meaning and accepts her role as potential queen, she does have her moments of being rebellious and a bit bratty. Protagonist of KQ4 and KQ7, but shares the latter role with her mother Valanice.
Spoiled Sweet: When she's not being a Royal Brat, she's this instead. Her parents spoiled her like mad to make up for Alexander's disappearance, but she usually cares about being a good and fair future queen anyway.
Tomboy Princess: She'd rather be romping around having adventures than being a prim princess, and in her youth she often liked playing with sporting equipment and other boyish activities.
The male half of the Royal Twins, who spent most of his life kidnapped and raised as a wizard's slave named Gwydion. Tends to take after his father in looks and his mother in personality. Outwardly calm and well-mannered, but with a core of craftiness, passion, and self-doubt. Also, give him a Spell Book to work from, and he's a dangerously competent sorcerer. Protagonist of KQ3 and KQ6.
Badass Bookworm: He may be a calm, quiet, pretty-boy scholar, but that doesn't stop him from being able to kill a dragon, challenge Death, and hold his own for a time with a giant-ass sword almost too heavy to lift.
Beneath the Mask: Despite returning home to a loving family and the rank of prince, he still thinks of himself as the slave Gwydion, and the "Alexander" identity as a cloak or a mask. He makes consessions to both identities by signing his papers "Alexander-Gwydion"
Brainy Brunet: The Extended Universe paints him as being almost a straight-up medieval Geek, if more good-looking and well-mannered than average. He spends a fair bit of time teaching at the Royal University and studying magic, pens several textbooks himself, and the Companion comments that he holds for Cassima a "passion previously reserved only for books".
Clueless Chick Magnet: Attracts a number of admirers in the series, including a spider in King's Quest VI, a barmaid in the Fan Remake of King's Quest III, and a princess in one of the Tie-In Novels, but still worries Cassima won't find him attractive.
Utility Magic: The only type of magic he's been shown to be able to cast so far, though it does include things like inducing storms. Still extremely dangerous with it anyway.
A fairy prince who's the son of King Oberon and Queen Titania, but was kidnapped and raised for a long time by the evil witch Lolotte. It was when Rosella came to defeat Lolotte that he met her, and was subsequently rescued and returned to his family. He later met up with Rosella again when he was kidnapped by his aunt Malicia and made to pose as the Troll King to help her with a scheme.Features in KQ4 and KQ7.
And Now You Must Marry Me: Does this to Rosella twice, though once it was Lolotte who invoked it on his behalf and he felt guilty and eventually helped Rosella escape it, and the second time it was while he was Brainwashed and Crazy disguised as the Troll King.
Baleful Polymorph: Poor guy seems to keep suffering these. First into an ugly green hunchback as Lolotte's "son", then as a duplicate of the Troll King.
Boy Next Door: While not literally the boy next door, he nonetheless fits this personality type rather well, coming off as more of an Average Nice Guy than a blueblood even after he gets to go home.
Standard Hero Reward: Actually offers himself as this to Rosella after she helps him escape Lolotte, but she turns him down because she has more pressing concerns at the time. Later on when they meet again he asks her to let him court her instead, and she accepts.
Princess of the Land of the Green Isles, Cassima is first met as a serving girl in Mordack's Castle in King's Quest V, where she meets the Royal Family of Daventry. Alexander is smitten and King's Quest VI involves him journeying to the Land of the Green Isles to see her. Alexander and Cassima marry at the end ofKQVI, and ascend to the throne.
Badass Princess: While not as action-y as Alexander, she's certainly not afraid to wade into the fray with a dagger.
The Smart Girl: Jollo and the ferryman both mention that Cassima has a good head on her shoulders, and she does think of a few clever plans.
Unkempt Beauty: To an extent, in that Alexander falls for her even while she's trapped in Mordack's castle dressed in slave rags and her hair a mess (though she's still wearing makeup for some reason).
Of course, the slave attire wouldn't put Alex off seeing as the poor kid still thinks of himself as a lucky slave
An old Evil Sorceror who's the Sorcerous Overlord of Llewdor, and lives in a mansion overlooking the country. His nastier habits besides terrorizing Llewdor's citizens involve enslaving young boys to do his chores until they come of age and he disposes of them, and dispatching his adversaries via turning them into housecats. Brother of Mordack, an equally Evil Sorceror. He shows up in KQ3 and KQ5.
Baleful Polymorph: Again, what he likes to do to his more powerful opponents and what eventually happens to him.
Spell My Name with an S: Even the games themselves manage to be inconsistent about how many Ns go in his name and where. Almost guaranteed any Let's Player will doof up saying it as a result, whether accidentally or as a purposeful lampshade.