Amulet of the Sun Eater

You have resistance to radiant damage. 

Once a day as a free action, you can speak this item's command word. When you do, spectral, astronomic wings sprout from your back, your eyes glow, and starlight begins to writhe around your limbs. For 1 minute, you gain a flying speed of thirty feet. Additionally, whenever you hit a creature for the first time in a turn for the next minute, the next creature besides yourself that makes an attack against that creature has advantage on the attack. Once you use this feature, you can't use it again until you finish a short rest.