Dark Aura

You surround yourself in death and shadow that fills a 10 ft square around you. The sphere goes around corners. Any creature that starts it's turn in the sphere (apart from you) must make a DC 20 Dexterity saving throw, taking 1d20 necrotic damage on a failed save, and half as much damage on a successful one. Also, any creature that can see you and has an intelligence score of at least 10 must make a DC 10 Wisdom saving throw or become frightened until your spell ends. At the start of each of it's turns, a creature frightened by you can repeat the saving throw, ending the effect on itself on a success.