Timeline

the planet skyworld coalesces in orbit around its parent star.

a comet strikes skyworld and "rains mana from heaven" in the form of biological material that feed on the hydrogen rich atmosphere.

giant continent-sized worlds float in great altitudes. feeding on the hydrogen. and through a process of biological cold fusion turn it into heavier elements that it secretes to its surface. while gases like helium are expelled to give it a floating equilibrium

asteroids strike many of the giant worlds. depositing new elements on them.

trough millions of years of evolution. several sentient species evolve on several of the worlds.