Stormfist is a Monster Set (Helm and Shoulder) available in light, medium or heavy armor. It drops in the Stormfist (unique) style.

The 1-piece set bonus adds 129 Stamina Recovery.

2-piece set bonus: When you deal damage, you have a 10% chance to create a thunderfist to crush the enemy, dealing 1650 Shock Damage every 1 second for 3 seconds to all enemies within 4 meters and a final 8000 Physical Damage when the fist closes. This effect can occur once every 8 seconds.

The Shoulder can be acquired by using an Undaunted key on Glirion the Redbeard's chest. The Shoulder type, weight and trait are RNG based and can be from any dungeon this NPC gives Pledges for.

The Helm can be acquired from Tempest Island which is part of the base game and located in Malabal Tor. The Helm is guaranteed to drop from the final boss in veteran mode only. The weight and trait are RNG based.

You can mix-and-match Monster Set shoulders and helms from different sets and add two 1-piece bonuses to your build, or wear a complete set to take advantage of the full 2-piece set bonus.