The details of norns, grendels, ettins and geats in games in the Creatures series - such as their brains, biochemistry and appearance - are to a great degree dictated by virtual genetics using a simulated genome; often called Digital DNA.
Things which are defined in genomes include:
- brain information (lobes, and the dendrites and neurons they contain)
- chemical reactions and half-lives (norns can become immortal and such things when these mutate)
- concentrations of chemicals in the bloodstream at birth
- biochemistry workings (receptors, emitters, and 'neuro emitters' which link with the brain systems)
- creature appearance; pose, pigments and gait, among other things