A novel pitched at age 10 and up, or thereabouts. (Work in progress.)  I've only dipped my toes into the vast array of RECords in the Shadow Collab; Soupy said it was okay if my worldbuilding diverged from the official line, so I'm running with that, because I've got a big storyline in my head, and it's a bit more like a Studio Ghibli movie than anything.

FYI, then, in this iteration of the Shadow World, shadows are specifically attached to individual objects and people, and they live only as long as their objects exist to cast them. The tiny, shortlived shadows of mayflies and petals and pencil shavings and the like have their own society, and are incomprehensible to the shadows in our story. These tiny shadows are known as fluttershies and dimflits.

The most ancient shadows (those cast by centuries' old trees, and by mountains and monuments etc) tend to stand around doing nothing much, almost like statues, and the shadowkin call them 'Shades' regardless of their caste, and think of them as mindless, much as we think of walls and trees and benches. (They're wrong about that, as it happens.)

Then there are the privileged sunshadows (longrays, midlights, noondays) and the outcast gloam and fauxbeams. The fauxbeams are not simply shadows cast by artificial light but, more specifically, the flimsy, fragmented shadows cast by myriad different light sources.

There is also a sixth caste: the fireflights. They are the shadows cast by candles and torches and campfires (etc) and as such they have always been there to listen to people spinning stories. They are the shadows who perform in shadowpuppet shows, and the shadows cast on the walls of the most ancient caves while prehistoric people shivered around their fires and listened to heroic tales of hunting and creation and betrayal. They are the shadows cast by flickering torches illuminating actors on the stage of Shakespeare's globe, and the shadows cast on the walls of romantically-lit restaurants, as trembling suitors propose or proposition.

The fireflights were exiled from Umbra & their memory all but obliterated; they were (indeed are) actors and teachers and tellers of tales, and they had traditionally been the guardians of the shadows' history before the longrays usurped them and exiled them. The fireflights do not worship the sun, and before their exile the shadow people in general did not idolise the sunlight.

When Flick the gloam stumbles across a great truth about moonlight, this discovery pushes her into a quest that will lead her to the Shadowking in his glittering palace, and to the fields where shadowkin are born, and into a dark and dangerous exile in search of the people who can help her bring the truth back to Umbra and change the shadow realm forever.