Aasimar are humans with an ancestor of good-aligned outsider blood, usually a celestial, and have great potential to do good. The legacy of an ancestor may show up in distant progeny, thus aasimar could be born to a couple of otherwise normal humans. They innately understand that they are special, whether or not they are aware of their ancestry, and usually find themselves drawn to higher pursuits such as paladin and cleric, because of their ties to the divine. However because of their mixed blood, they are marked as different and are sometimes given over to distant aloofness, or even bitterness, due to persecution or ridicule at the hands of others.

Aasimar should not be confused with half-celestials, who are a different species, rather than a subspecies of human. They have the appearance of a human except for one or two physical attributes that carry over from their lineage. Some examples are:

• golden, topaz or opalescent eyes
• silver hair
• emerald, silvery or golden skin
• feathers at the shoulder or in the hair
• a powerful ringing voice
• small patches of iridescent scales