The Apprentice Adept series is a seven-book fantasy and science fiction series by Piers Anthony. The series takes place on two worlds occupying the same space in two different dimensional planes: Phaze - a Magical Land in Medieval Stasis and more or less ruled by the Adepts, the strongest magic users, each specializing in a separate aspect, and Proton, a barren mining planet of high technology, ruled by the Plutocratic Citizens (who control the immense wealth of the Protonite mines). The worlds are divided by The Curtain, an energy field only visible to those capable of crossing it (someone without a doppelganger on the other side).The first trilogy (Split Infinity, Blue Adept, and Juxtaposition) starred Stile, a Proton serf who, after a mysterious assassination attempt destroyed his career as a race jockey, becomes the central figure in an ancient prophecy to Save Both Worlds from destruction, or ensure said destruction.The second trilogy (Out of Phaze, Robot Adept, and Unicorn Point) featured Bane and Mach, the sons of Stile and Stile's opposite number, Blue, and their efforts to keep the previous impending doom from happening all over again.The seventh and final book, Phaze Doubt sees both worlds dealing with an alien invasion, and the Batman Gambit meant to deal with it and prevent future ones.
This series contains examples of:
A.I. Is a Crapshoot: In this case, it's an Anti-Villain for the first two-and-a-half books, and indirectly responsible for most of the crap Stile goes through.
All of the Other Reindeer: the unicorn Neysa is an outcast because of her small size and horse-normal coloration. Most unicorns are technicolor.
Alternate Universe: Phaze to Photon, and vice versa. Not quite a Mirror Universe (because morality isn't reversed), but it otherwise fits the trope: people born on Proton have a counterpart in Phaze that is as close to identical to them as possible while still being consistent with the setting change. In particular, magical power in Phase translates as wealth and Game-skill in Proton.
Humans Are Special: Most species have some level of innate magic. However, only humans have the sheer power needed to become an Adept. A nonhuman with the Book of Magic becomes functionally somewhat stronger than a human Adept; a human with one has unlimited power.
Inevitable Tournament: nearly every major conflict is settled, once and for all, via the Great Game (or a variant, in Phaze).
I Have Boobs, You Must Obey!: The version of Tania in Proton doesn't have her Phase counterpart's Hypnotic Eyes, so when she desperately needs to convince a man to do something at a plot-critical moment, she tries the closest thing she can think of: flashing her breasts. It works.
It Only Works Once: Any specific Adept spell can only be used once, then variations have to be used.
La Résistance: When the Hectare invade in Phaze Doubt, the protagonist Lysander is a Hectare agent tasked with joining the resistance to figure out their plans and foil them. Subverted in that he falls in love with another resistance member and faces a conflict of honor.
Lawful Stupid: Piers Anthony's definition of "good." This is subverted whenever the good guys take advantage of Exact Words.
Les Collaborateurs: In Phaze Doubt, many Phaze/Proton citizens support the new regime to save their skins or profit, most notably the Tan and Purple Citizen/Adepts.
Let's Get Dangerous: Clef was a professional musician with little physical prowess. Put a rapier in his hand and it's Go Time.
Subverted by Mach, the Robot Adept, whose ability with the Book of Magic is bound by virtually no rules, and in fact explicitly breaks several pre-existing rules (such as the impossibility of crossbreeding).
To be fair, the Book of Magic is described as the nuclear age of magic whereas the normal Adept magic is like cave men using tools.
The biggest rule is the one-use rule. The blue adept needs a different rhyme for each new spell. The tan adept can only use the Evil Eye once on a given person. The yellow adept has a different appearance each time she takes a youth potion, etc. Even the Book of Magic adheres to this, but its wielder can use spells that are just a little bit different to reproduce the same effects with a little imagination, and another wielder can still use a spell that someone else has.
Magic Music: Stile's magic must be invoked via rhyme and is strengthened by the use of music.
Clef's ability with the Platinum Flute allows him to do something that none of the other Adepts can: manipulate the Curtain that separates Proton and Phase.
Magic Versus Science: Magic doesn't work in Proton. Technology more advanced than a horse-and-carriage doesn't work if ported over to Phaze. Stile was able to get around this in the first trilogy by having the Brown Adept animate Sheen the robot as a golem.
Several characters choose their names from events and objects of personal importance (Stile, Rifleman, Clef).
Werewolf naming has four stages: First syllable given at birth, second when pups are made official pack members (around age 6), third after a first successful solo hunt and fourth after First Mating (traditionally taking their partner's first syllable as their last). A werewolf isn't considered a full adult until they gain the fourth syllable.
Merged Reality: The two worlds are eventually merged into one; as the characters are explicitly paired across both worlds (mirror-universe twin kinda thing), each pair merges into one being, and each pair has to time-share their body. Substantially easier for the heroes than for the villains, since heroes are used to putting the needs of others on par with or ahead of their own.
No Name Given, Only Known by Their Nickname: The real/birth names of most of the human cast are never revealed. Also, serfs are required by Proton law to call Citizens "Sir", unless given explicit permission for other forms of address. Similarly, the Adepts in Phaze adopt their titles as their names: the Blue Adept is called "Blue", the Red Adept is called "Red", and so on.
No Nudity Taboo: Serfs on Proton are not allowed the privilege of wearing clothing. (There is an exception for safety gear.) This has made them indifferent to nudity and enhanced the appeal of sexy clothing.
One Judge to Rule Them All: How Stile won his harmonica duel against Clef, despite Clef giving what was clearly the superior performance. (The judges gave Stile the victory because he was a better *supporting* player; during their duet, playing with Stile produced a bigger improvement in Clef than playing with Clef produced in Stile.)
Prophecies Are Always Right / Prophetic Fallacy: In Juxtaposition, Stile was told he would be betrayed by "a young-seeming woman" and concludes it already happened, when Merle turned him in to the Citizen coalition. It turns out, however, that the true traitor was Brown...except in a Double Subversion, not only did she not know she was a traitor (she accidentally cast the spell wrong to switch the cardinal directions, thereby reversing everything—though considering her crush, this may not have been accidental after all), but the betrayal actually ended up helping Stile in the end—since it allowed Stile to stay in Phaze by reversing where his spirit lay, putting it in the golem's body and Blue's in Stile's. This last was anotherProphetic Fallacy—everyone assumed "Blue must leave Phaze forever" meant Stile since he had taken up the mantle of the Adept after his death. But once Blue's spirit was taken out of its Soul Jar and put in a golem body, he was the one who had to leave Phaze, and did.
Psychic Link: Mach and Bane, Flach and Nepe (Stile and Blue presumably can do the same but choose not to find out)
Rape as Drama: One of the sections of Unicorn Point'sTournament Arc pitted Tan against Agape in a "Seduction by Proxy" matchnote two volunteer serfs were selected and placed in a social situation where they took turns trying to imitate sex. Their memories of the game would be wiped afterward., where rape was allowed to "ensure a finish." Tan's proxy ended up raping Agape's proxy. Though the rape was treated with less drama than the fact that the good guys lost.
Retcon: The third generation protagonists get their nature and power level changed radically between when they were background and major characters.
Self-Fulfilling Prophecy: The Red Adept only tried to kill Stile because the Oracle said that Stile would destroy her, but Stile only fought her because she struck first.
In a more series-wide sense, the Oracle does its best to make sure all its prophecies come true, aided by the fact that it is a magical computer which can therefore work across both frames, and that it has contacts with the self-willed machines, including the Game Computer.
Serious Business: In a world where losing a game of Rock-Paper-Scissors can mean getting booted off the planet, everything possibly included in the Great Game is treated as Serious Business. Also, oaths on Phaze (which are magically enforced).
Soul Jar: Stile's harmonica, which contains the soul of the original Blue Adept.
Story Breaker Power: Mach has no limits on his powers as the Robot Adept. He's kept in check solely by Honor Before Reason; while he personally supports Team Stile, he's agreed to play by the rules that the Adverse Adepts set instead of simply blasting them off the map by force majeure.
Suddenly Sexuality: The revelation, after seven books, that Brown is a lesbian, and given a relationship with Tsetse.
Actually, there's a veiled reference to this in the fourth book when Mach, referring to Brown, says "She may have had some forbidden love of her own." in regards to Browns understanding of his love of Fleta.
Take a Third Option: In Stile's duel with the Herd Stallion in Blue Adept, Stile uses the Platinum Flute's power to ensure a fair fight between them, rather than using the power of the Flue to curb stomp the Stallion (humiliating him and making things even worse for Neyssa) or fight him without magic (resulting in Stile's stomping/humiliation).
Upgrade Artifact: The Book of Magic and the Platinum Flute. The Book lets anyone who possesses it to cast magic spells at an Adept's power level (It let a troll with no inherent magic become the new Red Adept). The Flute enhances the innate magic of anyone who holds it (allowing Stile, the Blue Adept, to use his magic withing the Anti-Magic influence of a unicorn circle). Anyone who can actually play the damn thing gains Adept-level magic. A master musician? Becomes stronger than all the other Adepts put together.
Voluntary Shapeshifting: A unicorn can take up to three forms (unicorn, human, and a third of their choosing, usually a bird or some sort of predator)note Though, if Belle is any indication, some stick with two forms if they eschew a human form. Similarly, werewolves can voluntarily change between human and wolf forms at will, while vampires have human and bat forms.
The original Herd Stallion takes this a step further, and succeeds in mastering a fourth Form after Stile persuades him that it would be uniquely helpful in getting them out of their current situation: the Cockroach.
What Kind of Lame Power Is Heart, Anyway?: Tan's Evil Eye grants absolute mind control; nifty, but other Adepts with more versatile powers can create spells to duplicate the effectnote although they need a new spell each time; see It Only Works Once in addition to the many, many other things they're capable of doing.
Why Am I Ticking?: In "Blue Adept", the hero is forewarned that the villain will try to force a magic bomb that will destroy him if he returns to Phaze with it. The bomb turns out to be a bullet, which the villain shoots into the hero, who realizes Just In Time what it really is.