While transformed through Celestial Revelation as a bonus action or reaction, you can use one of the following Halo effects while the transformation is in effect. Limited to one per long rest.
Celestial Aura. Your angelic presence radiates healing energy. As an action, you can activate your Celestial Aura, creating a 10-foot radius of soothing light centered on yourself. Any friendly creatures within the aura at the start of their turn regain hit points equal to your proficiency bonus.
Protective Wings. Your celestial wings offer a shield of defense. As a reaction, when an attack hits you or a creature you can see within 10 feet of you, you can manifest your wings and use them to provide protection. The target gains a bonus to their AC 1d4 until the end of your next turn or the creature moves away from you.
Radiant Blade. Your divine heritage empowers your attacks. Whenever you hit a creature with a weapon attack, you can add an additional 1d4 radiant damage to the damage roll(1d6 at a higher level).
Additionally, at level 9 while your wings are visible, enemies have disadvantage on attack rolls against you due to your captivating/terrifying angelic beauty.