Celestial Resistance. You have resistance to necrotic damage.
Night Magic. When you reach 3rd level, you can cast the Sleep spell once. Once you reach 5th level, you can also cast the Darkness spell once. You must finish a long rest to cast these spells again with this trait. Wisdom is your spellcasting ability for these spells.
Living Shadow. Your form contains a shadowy echo of itself, which you control. When attached to you, it gives your appearance a wispy dark outline. As an action, you can detach it from yourself, revealing it as an exact replica of your silhouette. It has AC 10, 1 hit point, and a Strength of 2, and it can't attack. If it drops to 0 hit points or becomes more than 60 feet away from you, it disappears and becomes your outline again. On each of your turns, you can use your bonus action to mentally command the echo to move up to 15 feet and perform basic tasks, such as interacting with an object.