Ongoing Spell Effect

At-will, std, ranged; you set fire to the magical effect. If your casting result exceeds the spell's DC, then on each of the caster's turn starts, the spell effect loses 1 energy. If this reduces the energy to 0, the spell ends immediately. Otherwise, there is a failure chance proportionate to the remaining energy (e.g., a spell with 3 energy has a 1/3 chance to end, 2 energy has a 2/3 chance, etc.).

This can be used on any magical effect, even those that are not strictly spells. Assuming a creature of rank x manifesting an innate magical ability imparts it with x energy.

For one soul shard, you can cause 1 + rank rounds' worth of energy to be lost immediately.