If you're willing to use a custom Power or two, you can model the Warden Sword as an Item of Power like so:
WARDEN SWORD [-1]
Description: The Wardens of the White Council are famed for their magical, super-sharp, spell-cutting silver swords. This is one of those swords. It was created by Luccio, the leader of the Wardens, specifically for a single Warden.
Musts: You must be a Warden of the White Council, with an Aspect reflecting that.
Note: Warden Swords are canonically Enchanted Items. This is an alternate interpretation.
Skills Affected: Weapons.
Effects:
[-0] Specific Wielder. A Warden Sword is only magical in the hands of the Warden it was made for.
[-1] It Is What It Is. It's a supernaturally sharp sword. Weapon 5 for the rightful bearer, weapon 3 for other people.
[-0] Unbreakable. As an Item of Power, this item cannot be broken except with a magical ritual that opposes its nature.
[+2] One-Time Discount. A full-sized sword is tricky to conceal at best.
[-2] Might Over Magic. A Warden Sword can cut magical spells the way a laser cuts butter.
Works just fine for someone with no spellcasting, if you change around a few details.
It's not just a counterspell.
MIGHT OVER MAGIC [-2]
Description: You can shatter magical effects through physical force.
Skills Affected: Might, Fists, Weapons.
Effects:
Disruptive Strikes. You destroy ongoing spells by hitting them. Doing so requires you to roll your Might skill plus the weapon rating of your melee attacks (including Strength bonuses) against a difficulty equal to the spell's strength or complexity. If you succeed, the spell ends.
Parry Magic. You may use your Might skill plus half of any stress bonus you have from Strength Powers in place of your Athletics skill to defend against magical attacks and maneuvers.
Anti-Magic Attacks. You may use Fists in place of Might with this Power, but you receive no benefit from weapons while doing so unless you can wield them with Fists. You may also use Weapons in place of Might with this Power, but only if you are armed with a weapon suitable for use with Weapons.
Skill Over Magic [-0]. When you use your Might (or Fists, or Weapons) skill to defend against a magical attack with multiple targets, you may allow any number of other characters targeted by the same effect to use your defence roll in place of their own. However, you do not benefit from Strength or weapon ratings when using this Power.
Living Counterspell [-1]. When you use your Might (or Fists, or Weapons) skill to defend against a magical attack with multiple targets, you may allow any number of other characters targeted by the same effect to use your defence roll in place of their own.
Superior Might Over Magic [-2]. Add four to your Might (or Fists, or Weapons) skill when using it with this Power.