Apply Weakness

You self-inflict a small wound on your self with a substance that causes the type weakness you want to apply to your foe.

The target of the spell must make a constitution-saving throw against your spellcasting DC. When the saving throw fails the target now has a weakness against one of the following damage types:

Lightning, Force, Fire, Poison, Cold, Necrotic, Acid, Sound

If the target is successfull on the saving throw, the caste suffers 1D6 damage of the chosen type.