The world is covered by a vast forest of immense trees, in whose crowns are thirteen kingdoms ruled by thirteen living gods. Here is the sunlit realm of Canopy, where the gods ensure fair weather and bountiful food and maintain a great barrier to keep the people safe from the barbarians and the horrific monsters than haunt the lightless Understory and Floor.
Unar is a young woman serving in the Garden of Audblayin, the goddess of life. Her life is entirely devoted to her deity, and she has few ambitions beyond rising in status in the Garden. When Audblayin dies and her servants set out to search for her reincarnation, Unar becomes convinced that her destiny is to become the reborn deity's new bodyguard. After she is passed over for the search, however, she begins to resort to increasing subterfuge to fulfill this goal, beginning a search that will expose both the cruel underbelly of Canopian society, hidden truths about the nature and history of the Forest and its peoples, and a plot to literally topple the gods' rule.
This work provides examples of the following tropes:
- All for Nothing: Everything Ular does in the first book is for the purpose of learning magic, returning to Canopy, and fulfilling the fate she believes lies in store for her as the bodyguard of the reborn Audblayin, and is willing to justify rather extreme actions on the basis of the great destiny they will work towards. When it's revealed that Audblayin was reborn as a girl, and will thus take a male bodyguard, it becomes clear that everything she did — every betrayal, every abandonment, every death she caused and the aid she gave to Kirrik's destructive plans — served no purpose at all.
- Body Surf: In the climax of Crossroads of Canopy, Kirrik attempts to take over Ular's body when she's killed, fails thanks to Ular's protective amulet, steals Ekhis' body instead, is promptly assassinated, and then takes one of her servants' bodies to escape.
- Born-Again Immortality: The gods inhabit human bodies, live in them for finite periods of time, die, and are reborn as seemingly normal children to human families shortly thereafter, eventually regaining their memories during puberty.
- Death of the Old Gods: In the past, the setting was ruled over by the Old Gods, immense beasts with the intellect of people. Many centuries ago, however, the Thirteen Gods arose and rebelled against their predecessors, striking them down and stealing their powers, and took over rule of the world.
- Fantastic Caste System: Canopian society is divided into a number of strictly distinct social classes, generally divided by how much of the immense trees' canopy they do or don't directly control. Below the gods and their immediate servants, there are crowns who own the tops of entire trees, then internoders who own sections of trunks between two branches, then citizens who own the houses they live in. Below them are the stricken, impoverished laborers who own nothing and lead largely hand-to-mouth existences, and then the slaves.
- Fun with Palindromes: Understorians use names that read the same when said forwards or backwards — Canopians adopted into Understorey society "mirror" their old names to achieve this effect — to represent the ability to move both up and down the great trees. Exceptions to this, such as Frog and her eventual reincarnation, deliberately adopt asymmetric names to symbolize their desire to only move up towards Canopy.
- God of Thunder: Airak, the lightning god, presides over storms and thunderbolts. In Canopy, his main roles are trapping shards of lightning in glass containers to serve as lamps and, more crucially, controlling the strength and frequency of lightning strikes to prevent them from setting the whole forest aflame.
- Grand Theft Me: Kirrik can transfer her soul into others' bodies to avoid death or to replace a failing, aging body, forcing their own souls out and into whatever afterlife may exist. She plans to do this to Ular, but when she tries to do this in the climax her victim's god-bone amulet keeps her safe, so Kirrik steals the body of the rain goddess Ekhis instead. Unfortunately for her, however, a god's power resides strictly in their soul and she is left with a regular mortal body.
- Heroic BSoD: When it's revealed at the end of Crossroads of Canopy that Audblayin was reborn as a girl, and will thus take a male bodyguard, Ular's rationalizations for the things she did to become the god's bodyguard herself fall apart, leaving her to face the fact that she caused tremendous harm to a lot of people for no reason beyond baseless fantasies. This causes her to fall into a state of self-hating depression that lasts for the rest of the book. However, this turns out to be a useful turn of events later. One needs to genuinely hate their target to steal their magic — the stronger the hate, the more powerful the attack. By the time Kirrik tries to steal Ular's magic, the latter's self-hatred is far stronger that Kirrik's disdain for her and easily fends her off.
- Layered Metropolis: Even outside of the Layered World proper, Canopy has its own noticeably layered character. The gods and their servants live in the emergent trees towering above the city, with the citizens and wealthier classes immediately below them in the upper canopy. The poor and the slaves live in the city's lowest stratum, where light already begins to be occluded by the thick growth above and the locals can expect to be literally shat upon by people living further up. However, the lower layer is actually safer to walk around alone in — since nobody has anything worth stealing, there's not much crime.
- Layered World: The setting's trees are large enough that the layers of the forest's growth serve rather comfortably as this, each possessing a very distinct character from the others and being large enough to house entire cultures within itself. At the top are the emergent trees, where the gods make their homes. Beneath these is the Canopy, a sunlit realm where the bulk of civilization exists. Next down is the Understory, a gloom-shrouded world separated from the canopy by a magical barrier and inhabited by monsters and scattered tribes. At the very bottom is the swampy, lightless Floor.
- Malicious Monitor Lizard: Dayhunters are Understorian predators resembling immense monitor lizards. They are voracious, cunning and very dangerous predators with a taste for human meat, and are greatly feared.
- No Good Deed Goes Unpunished: Early in Crossroads of Canopy, Unar uses her magic to help a slave plant additional seeds in order to cover for another slave, who was too weak to do the work and would have been thrown to her death for it. The next day, the wear on her magic reserves causes her to be passed over when the gardeners are being judged for their power, costing her chance to venture out of the Garden and forcing her to remain a servant while her friends progress in station.
- Our Demons Are Different: "Demon" is used as a general term for the monsters and predators that roam the Understory and the Floor. In practice, these range from cunning and oversized but otherwise entirely normal animals to supernatural, primordial horrors such as chimeras.
- Physical God: The Thirteen Gods are, physically speaking, fully human — they have human bodies, can be harmed and killed like anyone else, need to eat, sleep and relieve themselves, and grow old and frail in the normal human pattern. The reason they are called gods is because each one possesses stupendous magical power over a specific part of nature, which they can share with their servants, and because they reincarnate into a new body every time they die.
- Reincarnation: All souls reincarnate into new bodies after death, but all memories of their previous lives are stripped away in the process. In this, the gods' unique status comes from their ability to regain the memories of all their previous existences when they reach puberty.
- Tree Top Town: The city-kingdom of Canopy is by necessity built entirely with the topmost parts of the world's immense forest. Dwellings are cut directly within the trees' trunks and branches, roads follow massive intertwined branches grown and shaped by the god of wood, and gaps are crossed by swaying rope bridges or ladders woven from lianas. The enclaves of its living gods are built in the forest's immense emergent trees, their tops lopped off to hold basins of earth and larger buildings.
- Tree Top World: The world is covered in a forest of titanic trees so large that an entire civilization exists on the branches of its upper canopy, living in cities carved within the great trees' trunks. A magical barrier separates Canopy from Understorey, a world of pillar-like trunks where little light penetrates, home to scattered pale-skinned people who live and die without ever seeing the sun and to ferocious monsters. The dark, mud-encrusted Floor at the very bottom is a thing half of myth for the natives of the Canopy. Almost everything is made up of wood, leaves and tree byproducts by necessity, and stone and metal are rare and precious commodities — metal is mostly available from a single magic tree that draws it up through its roots and deposits it in its fruits.
- You Gotta Have Blue Hair: Ekhis, the rain goddess, has grey and indigo hair.