in the Warhammer universe, an ancient race of giant amphibian superbeings.

They are largely responsible for the state of the World as it is today, having:

  • created the warpgates at the two poles
  • created all existing races on the planet through breeding
  • placated the creatures of the Warp
  • travelled the universe doing similar things to other planets

By some colossal error, they also brought about the destruction of the warpgates.
This caused:
  • the entities known as Chaos Gods to enter the material universe,
  • the creation of two continent-sized radioactive hellholes known as the Chaos Wastes
  • the corruption of early Man, Dwarfs and Elves.
  • the creation of the condensed warpstuff known as Warpstone
  • the almost complete extinction of their race, with the exception of their degenerate descendants, the Slann
The Old Slann also play an important role in galactic history; in the WH40K worldview the Slann's catastrophe occurs simultaneously on all Slann worlds in the galaxy, and has been postulated to have created The Eye of Terror.