Anti-magic sword

You summon a magical greatsword to your hand. This greatsword deals 2d6 slashing + 6d6 force damage on hit. While wielding this great sword you gain the following attributes : 

• You have advantage on all saving throws against spells and magical effects. 
• If you pass a saving throw you take no damage instead of half. 
• You have 8 charges of counter spell each count for one spell slot. If you successfully counter a spell of up to 3rd level you can send it back to the caster for 2 extra charges.
• You have 5 charges of dispel magic. 

Duration: 3 attacks or up to 1 minute.