Genasi refers to a collection of humanoid lineages which trace their roots to The Elemental Planes. In this context, "lineage" means that an individual adopts the unique racial traits of their lineage, but maintains aspects of their other ancestry in appearance.

There are 8 genasi lineages, corresponding to the 8 Elemental Planes. Most genasi are born as a result of exposure to high levels of elemental energy during development, others are the result of a humanoid and elemental coupling.

Relation to Other Races
Description

Physical Appearance
While genasi maintain elements of their base race in appearance, they also features which make clear their elemental heritage. Skin and hair color and texture are the traits most often altered by elemental heritage.