2 items: Adds 12-1096 Maximum Stamina
3 items: Adds 9-833 Weapon Critical
4 items: Adds 1-129 Weapon Damage
5 items: Adds 30-345 Weapon Damage to your damaging abilities when you use them to attack an enemy from behind.
The set consists of medium armor and jewelry in all slots, as well as weapons and shields of all types.