Cursed sight of Theia

Radiant light emits from the user's eyes. Each creature in a 120-foot cone must make a Dexterity saving throw DC15. A creature takes 10d6 Radiant damage on a failed save, or half as much damage on a successful one.

The user can not cast any spells or use any attacks during the effect and must take an action or bonus action to end the effect. The user may also use a reaction to end the effect at the end of another creature's turn (similar to a legendary action).

For every turn that the effect is active the user will receive one point of exhaustion, the user can also sacrifice a minimum of four spell slots per turn to prevent exhaustion