5e Tieflings get all the love, which is a shame, since Aasimar have some serious potential. The Tiefling write ups are solid power levels, with neat abilities, and cool fluff. Aasimar, their counterpart, are cool fluff, but their abilities are mechanically weak. I’ve seen many a 5e Aasimar player use their Revelation ability, only to be underwhelmed. This is my mod to bump up the Aasimar a little bit. WoTC has tried 3 times now, and that’s probably the last time we will see it. 

At its core, an Aasimar is the descendent of a celestial being. The Tiefling is someone who looks like a devil, and either leans in or out of it. People think they are a monster, because they are, and its a suitable dark character, or people think they are a monster, and they aren’t. Rather, they are a normal person trying to get by and forge their own path in spite of society’s assumptions. I think the latter is more common for players, since good parties are more common than evil. Aasimar should get the same situation. People think they are good aligned outsiders. Whether because they are, which is pretty straight forward, or because they aren’t. Again, I’d argue the second is more interesting, and it doesn’t have to mean the Aasimar is against type and evil, they should simply be average, not a crusader for good, and they have to deal with constant folks seeking them out for blessings, or roping them into quests. For Aasimar, we are going to have a couple of subraces that lean into these options. We are also going to dip into the human parentage alongside the celestial. 

While I recommend you use the variant rules allowing +2 to one, and +1 to another of your choice, since it isn’t 100% that every group is using it, I included the ability scores as normal. 

Aasimar

Size: Small or Medium. Aasimar’s base size mirrors that of their parents. An Aasimar descendant from halflings is small, and one from Orcs is medium. An Aasimar descendant from giants would be large, or even huge, but is not suitable for players.

Ability Scores: +2 Charisma

Celestial Resistance: You have resistance to radiant damage.

Darkvision: You have Darkvision. 

Mundane Heritage: Pick another playable race to serve as your mundane heritage. You qualify as a member of that race for the purposes of prerequisites, spells, and abilities. EX: A Dwarven Heritage Aasimar can take the Dwarven Fortitude Feat from Xanathar’s Guide to Everything.

Celestial Heritage: Choose one of the following Celestial Heritage’s at first level. 

• Arcadian: A descendant of Arcadia, you naturally fall into patterns of law and order. Without thinking, you end up marching in step with your allies, and know exactly how many arrows are in your quiver. An Arcadian is always proficient with light and medium armor and shields, and gains a +1 bonus to their Strength score. Your precision is legendary, you add the true strike cantrip to your list of cantrips known, and 1/Long rest you can cast this cantrip as a bonus action.  If you don’t normally have a spellcasting ability, you can use your charisma for this spell. 
• Beastial: A descendant of the Beastlands, you possess an innate familiarity with animals and the natural world. You can speak with animals as though you shared a language, gain +1 Dexterity, and can choose two of the following abilities.
  • Your hands end in curved talons or sharp claws. You can make unarmed attacks with them dealing 1d4+strength modifier slashing damage.
  • You have an impressive horn, set of horns or antlers. You can make unarmed attacks with them dealing 1d4+strength bludgeoning damage.
  • You have the feathered wings of an eagle which grants you a fly speed of 30ft.
  • Your neck houses a set of gills in addition to your lungs, allowing you to breath underwater as if you were a fish.
  • Your skin is covered in scales, granting you an armor class of 13+Dexterity modifier. 
• Bytopian: A descendant of the Twin Paradises, you are at home in the space between. You gain +1 Dexterity, and the ability to control subjective gravity in a few ways. First, your base movement speed is set to 40ft (Increasing again by 10 additional feet at levels 5, and 15). Second, with an acrobatics check, you can balance on objects that would never support you. Lastly, once per long rest you can use the Reverse Gravity spell on a specific creature or object touched.
  • Acrobatics 
  • DC 10 – Walk across a thin rope or tree branch 2 inches in width that would otherwise support at most 20lbs. 
  • DC 15 – Walk across water or liquids (note if the liquid is caustic, like acid, your feet may still burn or take damage)
  • DC 20 – Walk across gasses and clouds (this enables a rudimentary form of flight)
• Elysian: As an Elysian, your natural state is one of good and healing. You can’t help but help others, and gain +1 Wisdom and proficiency in the insight skill to gain a sense of the nature of those who need help. In times of danger, as a bonus action, your skin can glow as per the light cantrip. Suppressing this glow is also a bonus action. Lastly, you can heal those in need with a touch. As an action, you can touch a creature, restoring hit points equal to your Wisdom modifier. If the creature has hit die, they can spend one now to regain additional hit points as though they had taken a short rest. You can use this ability one time per point of proficiency bonus per long rest.
• Heaven Sent: Your ancestors hail from Mount Celestia, and have shaped your beliefs with law, justice, and mercy. You gain +1 to Wisdom, and access to the following abilities once per short rest each. Bless, Sanctuary, and Shield of Faith. You use your Charisma for determining saving throws if needed. 
• Olympian: A native of Arborea, you pride yourself on your strength and athletic prowess. You gain +1 strength and proficiency in the athletics skill. You gain the powerful build trait, and your speed is not reduced in heavy armor. Lastly, when engaged in any opposed athletics checks, or checks performed with gaming sets, you roll with advantage.
• Ysgardian: As an aasimar from the Heroic Domains, you relish in a challenge, and are known to overcome all odds. You gain a +1 bonus to your constitution score. Once per long rest, per point of proficiency bonus, you can spend a hit die as an action to regain hit points as though you had taken a short rest. You can only spend one hit die per action in this way. Lastly, ysgardian aasimar also gain a form of malleable resistance. They have resistance to the last type of non-bludgeoning, piercing, or slashing damage they took. If they already have resistance from another source, the two instances of resistance do not stack.
• Rejected: Either you are descended from a celestial being who doesn’t acknowledge your heritage, or you reject your celestial heritage. Either way, this manifests itself with dark abilities. Your skin is an unearthly white, and eyes are pools of red. You naturally have feathered wings, which grant you a fly speed of 30ft, and your rejection of the celestial changes your radiant resistance to necrotic instead. Additionally, you gain proficiency in the deception skill and a +1 bonus to your Constitution score. Lastly, rejected aasimar have an affinity for dark or evil gods.You automatically know of the presence of evil aligned celestial beings and devils within 100ft. This ability also gives you advantage on ability checks and skills checks with them, and they automatically regard you as a friendly acquaintance. 

Embrace/Reject Heritage: At any point through narrative play, the player of a Rejected Aasimar and the DM can agree to recognize your character’s Celestial Heritage. To do so, they remove the benefits of the Rejected Heritage and apply the benefits of their new one. Likewise, any Aasimar can reject their heritage and choose the Rejected background, following the same process. These transitions are life changing events, and should be done no more than once every few years (if that), and only after significant revelations.

Languages: You can speak, read, and write common and one other language as determined by your mundane heritage. 

Appearances: Most Aasimar share the following traits, modified as needed for their Celestial Heritage. Aasimar look like others of their mundane heritage, with notable exceptions. Their skin comes in a variety of unnatural ivory, onyx, silver, and gold. Their eyes lack pupils and are usually a solid gold, or silver, or rarely violet. Aasimar hair is almost always a stark white, but occasionally goes as dark as platinum blonde, and may have streaks of a variety of colors throughout. Aasimar with wings tend to have feathered wings with white or light gold plumage. 

New Feat: Dual Heritage

Prerequisite: Aasimar

Benefit: You can choose a second celestial, or mundane heritage gaining the benefits of both.