Beware of unmarked spoilers.

!Septimus Heap
The main character, Septimus is a seventh son of a seventh son, wielding amazing '''Magykal''' powers.

* TheApprentice: Of Marcia Overstrand. She had been in fact waiting for him since long.
* CharacterDevelopment: At first, he's scared and rather antisocial. After the first book, he grows to be more confident and happy.
* ChildMage: He becomes [=ExtraOrdinary=] Apprentice at the tender age of ten years.
* [[spoiler:ChildSoldier: In the Young Army during his first ten years of life.]]
* DragonRider: He is Spit Fyre's rider.
* GreenEyes: He gets them after being recovered from the Young Army in ''Magyk'', as do all Wizard children when exposed to Magykal learning.
* MagicalSeventhSon: The main theme of the series is that seventh children of seventh children have extraordinary ''Magykal'' abilities.
* MeaningfulName: Septimus is the seventh son of a seventh son. His name means "seventh" in Latin. [[spoiler:Furthermore, his Young Army "name" was Boy 412, and 4+1+2=7.]]
** Reaches ArcNumber level when in ''Queste'', Marcia Overstrand is revealed to be the 776th [=ExtraOrdinary=] Wizard (remember, the first Wizard came sailing in from ancient Egypt), which will eventually make her apprentice, Septimus, the 777th.
* NiceGuy: He is genuinely compassionate towards others and doesn't regard anyone with malice. He even offers a second chance to [[spoiler:Simon]].
* SwitchedAtBirth: With Jenna.
* TookALevelInBadass: Septimus timidly starts off as TheLoad, but gets much better as his magical skill improves.
* TookALevelInJerkass: In ''Darke'', partly as a consequence of the imminent Darke Week and its tribulations.
* [[WhyDidItHaveToBeSnakes Why Did It Have To Be Heights?]]: Explained in ''Queste'', all powerful Wizards have a tendency to have fear of heights.

!Jenna Heap
The daughter of Queen Cerys and Milo Banda. She was rescued by Marcia Overstrand when the Queen was shot, and subsequently adopted by the Heap family.

* ActionGirl: An on-and-off example.
* BerserkButton: Don't try to kill Septimus or else she will take you down.
* DisappearedDad: Milo's wherabouts weren't know until ''Flyte'', and his reunion with his daughter was rather less than friendly.
* EverythingsBetterWithPrincesses: Literally, as she uses her Queen authority, e.g in ''Flyte'' to force Stanley to lead them to Aunt Zelda's cottage and in ''Darke'' to get Septimus to explain what the Darke Week is.
* GenkiGirl: She's generally upbeat.
* HappilyAdopted: She considers the Heap family to be her true family, almost more than her actual family.
* OneOfTheBoys: Courtesy of living with six boys, leading into...
* {{Tomboy}}: Although she doesn't mind wearing the tiara and dress that come with being queen, Jenna gives off slight vibes of this. She's certainly not scared to get dirty.
* PluckyGirl: Whatever happens, she won't let her spirits be dampened.
* PrincessesRule: Only in ''Darke'' does she receive "official" royal promotion.
* SwitchedAtBirth: With Septimus.

!Marcia Overstrand
The bossy [=ExtraOrdinary=] Wizard, she became EOW after her tutor Alther Mella was shot along with the Queen, and rescued Jenna in the same moment.

* TheArchmage: The [=ExtraOrdinary=] Wizard of the setting has high authority over other Wizards.
* GreenEyes: She's the main Wizard of the setting after all.
* JerkWithAHeartOfGold: Usually, she is very bossy and can be a huge annoyance to everyone, but when trouble abounds, she can be very caring and helpful.
* ParentalSubstitute: She is this to Septimus, according to WordOfGod.
* {{Tsundere}}: Marcia is a non-romantic variant she's self-centered and abrasive as all get-out, but she very clearly cares deeply for Septimus (when she slips enough to let it show).
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