Armor (medium or heavy, but not hide), legendary
When user draws in water a portion of it goes to the armor creating a thin endoskeleton of ice making a layer of protection (Protects 10 dmg refills every 3 turns). Made from adamantine, one of the hardest substances in existence. While you're wearing it, any critical hit against you becomes a normal hit.
Shields require the Utilize action to Don or Doff. You gain the Armor Class benefit of a Shield only if you have training with it.
Notes: Immunity: Critical Hits, Combat, Warding