Agony

Inflicts increasing agony on the target.
The target makes a wisdom saving throw, taking the damage as listed below on a failed save. On a successful one the damage for the duration is halved. Damage starts low and increases over the duration. Casting the spell again on the same target, forces a new saving throw, refreshes the duration, keeps the current Damage Die and increases the amount of dice by one.

If you cast the spell it deals the following damage as necrotic damage each round at the beginning of the targets turn. 

1. 1d4
2. 1d6
3. 1d6
4. 1d8
5. 1d10
6. 1d12

If you have the Shadow Embrace Feature, you can use it on each damage roll.

If you cast this spell using a higher spell slot, the number of dice rolled for damage are equal to the spell level.