* FollowTheLeader: Or InspirationForTheWork depending on the author's intention. Most obviously, ''Literature/HarryPotter'':
** Septimus to Harry (VERY similar backstories, though the former's parents are still alive)
** Beetle and Jenna to Ron and Hermione (some aspects of the latter duo may have been switched around, making the "Ron" character (Beetle) the smarter one and the "Hermione" character (Jenna) part of a family with many siblings; also, the former duo don't argue as much)
** Marcia to Dumbledore and [=McGonagall=] (a mix of the two)
** the Heap family to the Weasely family (poor family of magic users with many children)
** Merrin Meredith to Draco Malfoy (social status aside)
** the Castle to Hogsmeade
** the Wizard Tower to Hogwarts (and subsequently Septimus' seven years of education)
** the ghosts from both series (with varying rules of death)
** Alther to Dumbledore (again?)
** Turtius Fume to Severus Snape ([[spoiler:the former lacking the redeeming qualities of the latter, or at all]])
** [[spoiler:the Ring Wizards]] and maybe [=DomDaniel=] to Voldemort
* TheOtherDarrin: For all voices and reading of the audiobooks after ''Magyk'', which was read by Creator/AllanCorduner, who is known for numerous television roles, and has read audiobooks for several other popular titles. All later installments in the series were read by Gerard Doyle (reader of the audiobooks of ''Literature/InheritanceCycle''), and while he does a reasonable job, no attempt seems to have been made to emulate the voices used in the audiobook of ''Magyk'', and some, such as that of Marcia, are ''very'' different. Also, the ''[=TodHunter=] Moon'' books are this for everyone from the original cast, as they appropriately are read by a female narrator, Nicola Barber, because the main character in this series is female.
* ScheduleSlip: There was an almost one-year delay in the publication of ''Darke'', and the next book, ''Fyre,'' was only published in 2013. After that, however, things settled down, with the first book in the SequelSeries, ''[=TodHunter=] Moon: [=PathFinder=]'', published the next year.
* ShrugOfGod: Angie Sage is not always interested in explaining things.
* WordOfGay: Angie Sage mentioned that Sam Heap and Wolf Boy are gay. During a Q&A with fans she explained it likely wouldn't be mentioned or shown due to the ages of the characters, but was interested in the possibility of showing it during a ten year time skip epilogue.
** The two are shown traveling together as companions in the sequel series, Wolf Boy now known as Marwick, but it's never really said that they're gay.
* WordOfGod: [[http://septimusheapblog.com/ The Official Septimus Heap Blog]] is dedicated to providing this.
* WritingByTheSeatOfYourPants. According to the author, she doesn't do much planning before writing things.
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