You know the thaumaturgy cantrip. When you reach 3rd level, you can cast the hellish rebuke spell as a 2nd-level spell once with this trait and regain the ability to do so when you finish a long rest. When you reach 5th level, you can cast the darkness spell once with this trait and regain the ability to do so when you finish a long rest. Wisdom is your spellcasting ability for these spells.

Your split heritage gives you the opportunity, like your ancestors, to draw on inner power. But this power is in conflict with itself and what you unleash is an image of your soul in turmoil. 

Starting at 3rd level, you can use your action to unleash the conflict within yourself, causing a flaming halo to appear above your head and two black, angel-like wings to 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 every target of your choice within 15.ft of you that can see your transformation has to make a DC (8 + your proficiency bonus + your Wisdom modifier) or become frightened of you until the end of your next turn. During it, once on each of your turns, you can deal extra necrotic damage or radiant damage (your choice) to one target when you deal damage to it with an attack or a spell. The extra damage equals your level.

You can use this trait a number once before needing to do a short rest to use it again.

Your Charisma score increases by 1, your Wisdom score increases by 1, and two scores of your choice increase by 1 each or one score increases by 2.

Aasilings mature at the same rate as humans, but they can live up to 160 years.

Imbued with celestial power, but also with fiendish power, Aasilings are often at the ends of neutrality, those who embrace their fiendish side turn to evil, and those who turn to their celestial nature are often good.

Aasilings have the same range of height and weight as humans.

Your base walking speed is 30 feet.

Your conflicted soul, bearing both fiend and celestial, have some advantages. Your soul has mixed both natures and created a superior darkvision, allowing you to see in darkness.

You have resistance to radiant damage and fire damage.

As an action, you can touch a creature and cause it to regain a number of hit points equal to your level. Once you use this trait, you can’t use it again until you finish a long rest.

You know the light cantrip. Wisdom is your spellcasting ability for it.

You can speak, read, and write Common and Celestial. In addition you choose between either Infernal or Abyssal.