All warforged group. The PCs are artificial intelligences that have been partially corrupted in aeons of slumber. Their memory banks and magical processors, which allow them to perceive and understand the reality surrounding them and interact with it via actions and movement, have been damaged.
They can regain slowly control of their inner core by venturing forth, exploring and experiencing the world around them.
They organize space in their mind's eye as a grid. They analyze movement based on artificial units of time. Some, most moves they can still perform without much strain from their data banks, while others override their systems and create shortcuts which require some time for them to process and correct to perform again. Generally a few minutes without intensive activity are enough, but sometimes a full system shutdown of a few hours at a time is necessary. They can recover from physical damage extremely fast, assisted by the nanobots that keep their systems running, even deriving surges of energy to rerout fuels in the middle of a fight when necessary.
They each have particular moral and ethical allegiances that have been programmed into their core. And ways to uncover their deeper purpose, their path of destiny, which has too been implanted into their core magical nucleus at birth, as their systems reacquire full functionality through the experience they gain from interacting with the world...
Countless years into the future, the earth has largely been abandoned by the human race who became refugees among the stars, seeking and colonizing new worlds.
Since planets are not always immediately habitable to humankind, terraforming of potential new homeworlds is carried out via nanobots which are linked to a central AI within each ARK ship while the human passengers rest in cryostasis. The terraforming makes the environment hospitable for the humans, but some of the planets physical properties...like space, time, gravity, etc. are a bit...off.
Not all of these planets were uninhabited when they were terraformed, some had indigenous creatures that suddenly found themselves having to adapt to an environment that is slowly becoming more and more hostile to them.
By this time, technology has become so ubiquitous and so user-friendly that humans can interface with on a biological level, using their unique bioelectrical signature as a sort of cellular IP address. Most people only perform basic day-to-day functions, and are only granted basic "user" status. Some however, need to perform maintenance and correct errors with the ARK AI. These people are granted "Admin" status and have special privileges within the system.
Then a cataclysm happened within network connecting all of the ARK ships. A virus or something of that nature destroyed a lot of the data from ship to ship and disrupted the life support systems. The ships had to make emergency landings planetside or lose all of the people hibernating within them. Furthermore, the cataclysm caused the sleeping populace to lose large portions of their memory, leaving only their most basic instincts and human intelligence intact.
Finding themselves awakened in a strange land with no memory of how they arrived, only that they seem to have come from a god named "ARKAI" the people begin to learn and evolve and rebuild. That was 11,000 years ago.
PC's play denizens of one of these worlds, with no notion that everything runs on futuristic technology. The planes are actually other colonized planets that have developed much in the same way that theirs has, and is linked via spacefold.
Most people in these worlds are simply "users" and are bound by the rules of the system. PC's are "admins" and can bend the rules int heir favor, even if they're not quite sure how they do it. Powersources more are like different coding languages than anything else, so arcane would be PERL to divine's C#, etc.
Different humanoid races are merely humans that have evolved in different environments.
Monsters are the planets former inhabitants, who were mutated by the terraforming of their homeworld.