In astronomy, there's something called being "tidally locked." That is, something orbiting something else has its own rotation equal the orbit period. In fact, our own moon is tidally locked with the Earth. We only ever see one side of it. If the Earth were a star, the part of the Moon that was towards us would always be light, while the other side would always be dark. That's what's happening in Siran, a world that has part always in light and part always in shadow. You can adventure in this world in the Between Sun & Shadow: Second Edition book that's up on Kickstarter now.
From the campaign:
Explore a land divided between the Unblinking Sun and the Everlasting Shadow in this officially licensed campaign setting for Tiny Dungeon 2e.
Between Sun & Shadow 2e is a sandbox-style campaign setting infused with advanced alchemy, clockwork technology, and a powerful new magic system.
Between Sun & Shadow 2e allows you to explore Siran, where half of the world lives in perpetual daylight, while the other experiences continuous darkness. The wondrous creations of master alchemists and clockwork engineers help create a thriving society, and a once forgotten magic known as Carving is being rediscovered. Those who unlock its secrets may be the ones to protect and preserve the Eternal Empire, or they may be the ones to end the reign of the One True King.
Between Sun & Shadow 2e is a sandbox-style setting. Filled with scores of Rumors that act as adventure hooks, it is up to you and your fellow players to explore what’s true and what’s false, who’s good and who’s bad. It is designed to be fully compatible with Tiny Dungeon 2e and the TinyD6 ruleset. It includes:
- 5 Heritages – Cogor, Eku-uke, Muaj, Utarok, and Zlax'xon.
- Cogor: Diminutive four-armed masters of clockwork technology who make up for their small size with brains and battle armor.
- Eku-uke: Winged bird-men with a penchant for patterns and symmetry who search for their true purpose in life.
- Muaj: Sentient carnivorous plants resembling a humanoid-shaped collection of twisted vines with multiple enzyme-squirting mouths.
- Utarok: Tattooed creatures known for their raw physical strength who have raised their traditional body art to the next level with alchemical tattoos.
- Zlax’xon: Militaristic intelligent insects with a history of service and a strong sense of community.
- 50+ Traits & Prestige Traits including a powerful system of magic known as Carving, which allows Adventurers to manipulate elements, energy, people, and even time and space.
- 20+ creatures to fight or befriend.
- 100+ adventure hooks.
- A random adventure generator.
- A land of adventure in a tidally locked world, with descriptions of major cities, locations, and influential groups.
- A map of Siran by Gill Pearce.
- 20 pieces of art by Nicolás R. Giacondino.