Aasimar Lore

Aasimar bear within their souls the light of the heavens. They are descended from humans with a touch of the power of Mount Celestia, the divine realm of many lawful good deities. Aasimar are born to serve as champions of the gods, their births hailed as blessed events. They are a people of otherworldly visages, with luminous features that reveal their celestial heritage.

Falling from Grace or Rising to It

With your DM's consent, you can change your character's subrace to fallen Aasimar if your protector/scourge aasimar turns to evil. To do so, replace your subrace benefits, including the ability score increase, with those of a fallen aasimar. Similarly, if your fallen aasimar turns to good, your DM might allow you to become a protector or scourge aasimar.

Celestial Champions

Aasimar are placed in the world to serve as guardians of law and good. Their patrons expect them to strike at evil, lead by example, and further the cause of justice. From an early age, an aasimar receives visions and guidance from celestial entities via dreams. These dreams help shape an aasimar, granting a sense of destiny and a desire for righteousness.
Each aasimar can count a specific celestial agent of the gods as a guide. This entity is typically a deva, an angel who acts as a messenger to the mortal world.

Hidden Wanderers

While aasimar are strident foes of evil, they typically prefer to keep a low profile. An aasimar inevitably draws the attention of evil cultists, fiends, and other enemies of good, all of whom would be eager to strike down a celestial champion if they had the chance. When traveling, aasimar prefer hoods, closed helms, and other gear that allows them to conceal their identities. They nevertheless have no compunction about striking openly at evil. The secrecy they desire is never worth endangering the innocent.

Aasimar Guides

An aasimar, except for one who has turned to evil, has a link to an angelic being. That being—usually a deva—provides guidance to the aasimar, though this connection functions only in dreams. As such, the guidance is not a direct command or a simple spoken word. Instead, the aasimar receives visions, prophecies, and feelings. The angelic being is far from omniscient. Its guidance is based on its understanding of the tenets of law and good, and it might have insight into combating especially powerful evils that it knows about.
As part of fleshing out an aasimar character, consider the nature of that character's angelic guide. The Angelic Guide tables offer names and natures that you can use to flesh out your character's guide.

d6	Name
1	Tadriel
2	Myllandra
3	Seraphina
4	Galladia
5	Mykiel
6	Valandras

d6	Nature
1	Bookish and lecturing
2	Compassionate and hopeful
3	Practical and lighthearted
4	Fierce and vengeful
5	Stern and judgmental
6	Kind and parental

Conflicted Souls

Despite its celestial origin, an aasimar is mortal and possesses free will. Most aasimar follow their ordained path, but some grow to see their abilities as a curse. These disaffected aasimar are typically content to turn away from the world, but a few become agents of evil. In their minds, their exposure to celestial powers amounted to little more than brainwashing. Evil aasimar make deadly foes. The radiant power they once commanded becomes corrupted into a horrid, draining magic. And their angelic guides abandon them.
Even aasimar wholly dedicated to good sometimes feel torn between two worlds. The angels that guide them see the world from a distant perch. An aasimar who wishes to stop and help a town recover from a drought might be told by an angelic guide to push forward on a greater quest. To a distant angel, saving a few commoners might pale in comparison to defeating a cult of Orcus. An aasimar's guide is wise but not infallible.

Aasimar Names

Most aasimar are born from human parents, and they use the same naming conventions as their native culture.