These descendants are extremely rare, almost unheard of. From an early age they tend to receive visions and guidance from celestial entities or their fiendish blood in their veins via dreams. These folk generally appear as: glorious humans with lustrous hair, flawless skin (possibly A dusting of metallic, white, or charcoal freckles), and piercing eyes (Metallic, luminous, or dark), but sometimes they would have the appearance of Variant Tieflings as well: small horns; fangs or sharp teeth; a forked tongue; catlike eyes; six fingers on each hand; goat-like legs; cloven hoofs; a forked tail; leathery or scaly skin; red or dark blue skin; cast no shadow or reflection; exude a smell of brimstone.

These descendant do not begin with control over their abilities since they are not actually unveiled at birth. The timing in which their powers are revealed varies greatly with each individual. As they experience the channel and source of their powers, they may learn to gain control them or instead be control by them.  

* When using to channel their antitheses, your DM may decided which effect occurs or instruct you to roll to determine. When/if you attain a mastery of your bloodlines, your DM may allow you to decided*

Ability Score Increase

CHA +2 / CON +1

Age

Aasimar/Tiefling Descendants mature at the same rate as Humans but due to their rarity and strange nature, their lifespan is unknown.

Alignment

Due to their conflicting lineage, Aasimar/Tiefling Descendant tend to swing wildly on the alignment spectrum – often changing alignment as their two natures fight for dominance.

Size

Same size and build as Humans. Your size is Medium.

Speed

Your base walking speed is 30 feet.

Darkvision

Thanks to the influence of both extraplanar bloodlines, you have superior vision in dark and dim Conditions. You can see in dim light within 60 feet of you as if it were bright light, and in Darkness as if it were dim light. You can’t discern color in Darkness, only Shades of Gray.

Dual Resistance

You have resistance to fire and radiant damage.

Extraplanar Insight

You know the Thaumaturgy cantrip. When you reach 3 Level, you can cast the spell Protection from Evil and Good once with this trait and regain the ability to do so when you finish a Long Rest.

Languages

You can speak, read and write Common, Celestial and Infernal.

Channel Antithesis

Starting at 5 level, you can use your action to unleash either the divine or infernal power within yourself, causing one of the two effects to occur:

• Channel Radiance: Your eyes glow bright and two luminous, incorporeal wings sprout from your back. Your transformation lasts for 1 minute or until you end it as a bonus action. During it, you have a flying speed of 30 feet, and once on each of your turns, you can deal extra radiant damage to one target when you deal damage to it with an attack or spell. The extra radiant damage equals your level. For the duration your alignment shifts to Lawful Good if it was not already. You return to your previous alignment when the transformation ends.
• Channel Hellfire: Your eyes take on a black pitch and dark flames harmlessly dance across your body. Your transformation lasts for 1 minute or until you end it as a bonus action. During it, you can cast the spell Hellish Rebuke at first level without expending a spell slot, once on each of your turns, you can deal extra fire damage to one target when you deal damage to it with an attack or a spell. The extra fire damage equals your level. For the duration your alignment shifts to Lawful Evil if it is not already. You return to your previous alignment when the transformation ends. Once you use this trait you can’t use it again until you finish a Long Rest.