The books revolve around the adventures of fledgling detective Valkyrie Cain and her mentor Skulduggery Pleasant, along with other friends and allies.

[3] In October 2022, Landy announced via YouTube livestream that a "one-off prequel" and "Book 0·1", Hell Breaks Loose, would release in March 2023.

[4] In September 2023, Derek Landy announced via Twitter that there would be a third phase consisting of three books of the Skulduggery Pleasant series.

In early March 2024, Derek Landy announced via Twitter that there would be a podcast, titled "The Haunted House on Hollow Hill",which would be released in the summer of 2024, with audiobook, e-book and print versions coming out in September 2024.

Together with Ghastly Bespoke, China Sorrows, and Tanith Low, Stephanie and Skulduggery tried to stop a plot for world domination of Serpine, an evil sorcerer.

Serpine wanted to rule the world with the Scepter of the Ancients, a weapon used to defeat the tyrannical gods called the Faceless Ones.

At least, that is what Valkyrie and Skulduggery think, until the notorious Baron Vengeous makes a bloody escape from prison, and dead bodies and vampires start showing up all over Ireland.

With Baron Vengeous after the deadly armour of Lord Vile, and pretty much everyone out to kill Valkyrie, the daring detective duo face their biggest challenge yet.

As a number of teleporters are mysteriously murdered, Valkyrie and Skulduggery learn that it is quickly linked to a fanatical cult named the Diablerie, who seek to open a portal with the goal of returning the Faceless Ones to the world.

With the assistance of cocky young teleporter Fletcher Renn, Valkyrie and Skulduggery have very little time to track down a mysterious man named Batu, stop the Diablerie, and prevent the return of the Faceless Ones.

There's a gang of villains bent on destroying the Sanctuary, there are some very powerful people who want Valkyrie dead, and as if all that was not enough it looks very likely that a sorcerer named Darquesse is going to kill the world and everyone on it.

And then the body-snatching Remnants get loose, thousands of twisted souls who possess the living like puppets, and they begin their search for a being powerful enough to lead them.

With Skulduggery racing to catch up and young sorcerer Omen scrambling along behind, Valkyrie only has twelve hours to find Alice before it is too late.

The clock is ticking...[26] On a desperate journey to recover her sister's lost soul, Valkyrie Cain goes up against the High Sanctuary itself, and there is nothing Skulduggery Pleasant can do to stop her.

With Abyssinia's grand plan about to kick off in a night of magic, terror, and bloodshed, it falls to Omen Darkly to save the lives of thousands of innocent people.

And as the madness unfolds around him, as hidden enemies' step into the light, and as Valkyrie is sucked into a desperate, lawless quest of her own, he has no choice but to become the hero he never really wanted to be — or die in the attempt.

To avert catastrophe, Skulduggery and Valkyrie are sent on a secret mission that takes them away from everything they know, to a forsaken land of magic and grim, unrelenting terror, with the last Dead Men, Tanith Low, and Dimensional Shunter "Luke Skywalker".

Billions of lives will be wiped away in a final, desperate search for Alice, the Child of the Faceless Ones – she who is destined to bring about the return of humankind's ancient overlords.

With protests stirring in the magical city of Roarhaven, with riots and revolutions on the horizon, Valkyrie must decide who she wants to be: the hero who risks everything for a noble ideal, or the killer who sacrifices her own soul for the fate of humanity.

With the end of everything just days away – and no longer able to rely on Valkyrie Cain – Skulduggery must make allies of enemies if he's going to stand any chance of saving what is left of the world.

(6–7) In June 2011 Landy posted on his blog that he would be writing a short story about Skulduggery called The End of the World.

(7–8) A spin-off novel featuring Tanith Low taking place between the seventh and eighth books was released on 28 March 2013 in the U.K & Ireland and 1 April in other countries.

The Maleficent Seven: From the World of Skulduggery Pleasant) were released on 7 December 2012 after several delays, with Landy stating it to be his favourite book cover ever.

Tanith Low, now possessed by a remnant, recruits a gang of villains – many of whom will be familiar from previous Skulduggery adventures – in order to track down and steal the four God-Killer level weapons that could hurt Darquesse when she eventually emerges.

Landy may well revisit these characters – I sincerely hope he does – but it's a pleasingly rounded tale, which is refreshing in these days of endless open-ended books of never-ending series.

[42]Nathan Nicholls (Whitby Gazette): There is no expense spared by Landy in this book and I would have to say that everyone who could be bothered to read it, would definitely be drawn into it and certainly enjoy it.

[44]The Times: Derek Landy's debut, Skulduggery Pleasant (...) has a distinctly Horowitzian humour and verve to it, being a detective story featuring a wizard's skeleton as hero.

When Stephanie's uncle dies, she discovers his horror stories weren't fiction, and that evil forces are after her for a mysterious key.

A film adaption was in development under Warner Brothers but according to Derek Landy, the script was "the worst thing [he had] ever read", with Skulduggery Pleasant a "skeleton body who somehow retained his head and face", a magnifying glass magic wand,[52] and a musical number where he danced to Michael Jackson's "Man in the Mirror".

In interviews with the Irish Examiner and The Nerd Daily in March and April 2021, Landy confirmed he was continuing the development of a screenplay.