[PTTG]

Yeah, typo from an earlier version.

The worlds naturally have the same number of people, which is about 800 million. This is quite large for some and quite small for others. They all featured a massive war about 40 years ago, and a second, smaller war ten years ago which ended in an uneasy peace.

On all worlds, society is broken up into city-states rather than nations, and there is a complicated web of alliances and treaties that maintains some level of international order. This helps explain how history can be connected as it is over the broad spectrum of worlds.

1: TL 2+3 (subaquatic magic). The main sapient species is an aquatically adapted humanoid. Normal Mana and fairly common Magery.

2: TL 7. Despite different surface configuration, Human society is shockingly similar to 1950s Earth, although tech is more static and specific cultures are "scrambled."

3: TL 8, TL 9 in weapons, armor, and micromanufacturing tech. People live in corporate enclaves rather than city-states, but the alliances and other deals are all the same.

4: TL unclear, rough estimate based on the standard of living is TL 7. Horses are main transportation method, yet nuclear fusion is a common power source. Gunpowder is unknown, but combat lasers are standard. While overall standard of living is similar from one city to the other, weird scientists are very much the resident "wizards" of this society, making technology vary wildly from place to place.

5: TL 4+2 (Popular magic) Magic keeps the cities alive despite the harsh global winters and scorching summers of this world. High mana.

6: TL 3, amid very high-tech ruins. It's not clear what left the ruins behind, but it is clear it isn't human. The ruins, though unpowered, are not decaying, only.... sleeping.

7: TL 4 verging on TL 5. A strange form of ice is not only lighter than water, but also lighter than air, and it melts at about 60 degrees Celsius. It is found only in the polar regions under deep glaciers, but its extraction has already begun to fuel the production of many new designs of airship.

8: ~TL 10?. The "People" are computer programs running in a simulation of a TL 6 society that is otherwise a "normal" instance of this skery The world the computers themselves are in consists of a smother world packed with solar panels and server farms. The world of the simulation has a large number of simplifications that are merely a fact of life for the inhabitants. For instance, water is simulated as marble-like balls until it hits a natural body of water - a glasslike plane.

9: TL 5. A natural cloudlike phenomenon, or perhaps something more esoteric, has resulted in no sunlight reaching ground level, but mostly normal surface temperatures. Artificial light sources are the key to modern civilization. For some reason, plants still work.

10: TL 8+2 (magic). Normal mana appeared over a decade after the great war; everyone born after the awakening has magery.

11: TL 7. The only mass-market media is literature, and in general society revolves around the written word.

12: TL 4. Low mana, very rare magery, although practice allows mages to gain levels. Wizards are powerful kings, each one a master of a city-state.