War Echoes (Lorehold)

By pulling from the magic of the past, you can cause your opponent’s old wounds to resonate anew.

When a creature you can see hits a target with an attack roll, you can use your reaction to force the target to make a Wisdom saving throw (Your spell casting DC).
On a failure, the target becomes vulnerable to one of the damage types dealt by the attack.This vulnerability lasts until the end of the target’s next turn and affects the damage dealt by the triggering attack.

*Modifications of generic school mage stat blocks ability in Strixhaven for the 5 schools, can be added to NPC sheets to replace generic monster stat blocks suggested.