Beguiling Defenses

Your patron teaches you how to guard your mind and body. You are immune to the Charmed condition.

In addition, immediately after a creature you can see hits you with an attack roll, you can take a Reaction to reduce the damage you take by half (round down), and you can force the attacker to make a Wisdom saving throw against your spell save DC. On a failed save, the attacker takes Psychic damage equal to the damage you take. Once you use this Reaction, you can't use it again until you finish a Long Rest unless you expend a Pact Magic spell slot (no action required) to restore your use of it.