Spellbreaker

Martial melee weapon (greatsword), very rare (requires attunement) 

- You have advantage to saving throws versus spells and spell-like abilities while you're attuned to this weapon.

- You have a bonus of +2 to attack rolls and damage rolls with this weapon.

- While wielding this weapon, you can cast the counterspell spell (d20+5) once per short rest.

- When you score a critical hit against a spellcaster with this weapon, you inflict 7 additional damages.