Improved Mage Slayer

You have further practiced techniques useful in melee combat against spellcasters, gaining the following benefits:

• When a creature within your melee weapon reach casts a spell, you can use your reaction to make a melee weapon attack against that creature.
• When you strike a creature that is casting a spell, that creature must make a concentration check, with disadvantage on the saving throw, or the spell fails, and the components/spell slots are consumed.
• You have advantage on saving throws against spells cast by creatures within your melee weapon's reach of you.