You are a Humanoid and Celestial.

You are Medium or Small. Choose a size befitting of the mortal form you are disguised as.

Your walking speed is 30 feet.

You have resistance to necrotic damage and are immune to disease.

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 discern colors in that darkness.

As every angel was created to serve a purpose, you have studied a particular craft or with a particular weapon as part of your duties. Choose a tool or weapon proficiency that fits your purpose. 

As an action, you can touch a creature and roll a number of d4s equal to your proficiency bonus. The creature regains a number of hit points equal to the total rolled. You may use 2 of these d4s to cure the target of one disease or neutralize one poison affecting it.
Once you use this trait, you can’t use it again until you finish a long rest.

Hidden behind your mortal visage lies your wings, nearly incomprehensible to a human's perception. When in human form, an angel's wings are usually around twice as long as their height and only appear as a single set, but this can vary. 

You may temporarily unbind your wings so that you may fly. As a bonus action, you may bring out your wings and gain a flying speed equal to your walking speed for the next minute. Your wings glow with holy light, giving off 10ft of bright light and 10ft of dim light; the bright light is considered sunlight. These wings are not inhibited by physical things like armor.
You may call out your wings once per short or long rest.

Starting at 7th lvl, the time you can keep your wings out extends to 7 minutes.
Starting at 12th lvl, the time is extended to 40 minutes. 
Staring at 20th lvl, the time is extended to 3 hours. 

When you reach 3rd level, you can use an action to unleash a portion of your true angelic form. Choose one of the following auras to emanate depending on what lesson you believe you must teach. Once you release this angelic energy, you can’t do it again until you finish a long rest:

Aura of Love. For the next minute, a shimmery glow surrounds you. You shed dim light in a 30-foot radius. At the start of each of your turns, each friendly creature within 30 feet of you gains temporary hit points equal to half your level rounded down. They also have advantage on saving throws against effects that would make or keep them frightened. 

Aura of Wrath. For the next minute, a bright divine aura surrounds you. You shed bright light in a 30-foot radius and dim light for an additional 30 feet. Creatures in this aura of light have disadvantage on saving throws against effects that would make them frightened of you or stay frightened of you. At the end of each of your turns, each creature within 10 feet of you takes radiant damage equal to twice your proficiency bonus. 

Aura of Understanding. For the next 12 minutes, you can speak and understand the languages of any creatures within 30ft of you, and you have advantage on Insight checks on those individuals. You may speak telepathically if you wish. Creatures in this aura also have the urge to be more truthful and open than usual, but they can shake this feeling if they are particularly secretive. Unless they have truesight, other creatures cannot perceive this aura.