Prerequisites: 10th level, True Strike cantrip
When you cast the True Strike cantrip, you can concentrate on it for a number of rounds equal to your Intelligence modifier. You gain advantage on the first attack roll you make against the target each round while maintaining concentration on True Strike.
Whenever you deal lightning damage to a hostile creature using a warmage cantrip, you can sap part of the energy into a charge which clings to your body until the beginning of your next turn. While charged, you can use your reaction when you take damage from a creature you can see within 5 feet of you to deal lightning damage equal to half your warmage level to the creature.