Mage Slayer

You have practiced Techniques useful in melee Combat against spell casters, gaining the following benefits:

When a creature within 5 feet of you casts a spell, you can use your Reaction to make a melee weapon Attack against that creature.
When you damage a creature that is concentrating on a spell, that creature has disadvantage on the saving throw it makes to maintain its Concentration.
You have advantage on Saving Throws against Spells cast by Creatures within 5 feet of you.