Chose one of the following damage types: cold, fire, lightning, acid, or poison. You gain a breath weapon that can be used as a bonus action on your turn. Your breath weapon is a cone of raw energy that blasts out from your mouth and razes the 15 feet of anything in front of you, dealing 2d8 + Strength, Constitution, or Wisdom modifier damage of your chosen element. You can regain the use of this ability by using a bonus action on your turn to roll a d6, if the roll is 4 or higher, you can reuse this ability again on your next turn as a bonus action once more, if the roll is 3 or lower, you do not regain the use of this ability.

When a target is hit with this attack, they must make a Constitution save (Save DC is equal to your spell save DC), if they fail their save, they take an additional 1d10 necrotic damage.

You have large wings with slightly ragged webbing keeping them together. They can completely collapse as a natural appearing cape over your shoulders (you can roll a deception roll with advantage to convince others they are not wings if they are down). While your wings are up, you gain a fly speed equal to your walking speed.

You gain a +2 to Strength and a +1 to either Wisdom or Constitution.

Due to the strong magics in your once living bloodstream, your body undergoes a more drastic undead change than most Revenants. You gain resistance to necrotic damage but gain vulnerability to Radiant damage due to the polarity of the magics in your body.

This also means you have no need to sleep or breath but for some reason that isn't quite clear, you must still consume food of some sort  and take in a minimal amount of water to maintain your energy reserves, perhaps this is because of your primal instincts or considerably larger body type.

Finally, you gain dark vision, as a child of darkness, only magic can affect your ability to see in the deep night.

You are extremely close to the Raven Queen and given your more fearsome nature than an average Revenant, she keeps you close to her always. 

When you die, your soul immediately repels to the Queen's court where she determines if you're fit for resurrection or if your journey has come to an end. If the Queen allows you to return again, you will be given one of the following boons:

*The ability to retrain any number of skills from your class, background, Etc.

*A +1 to an  ability score of the Queen's choosing (to a maximum of 20)

*A peculiar magical item

*An automatic critical on the very next action you take, in or out of combat

*The return of another soul that you knew personally

You may petition the Raven Queen for 1 of these gifts particularly if she allows you to return to your corpse, but it is ultimately her decision to grant one of the boons.