2 items: Adds 12-1096 Maximum Magicka
3 items: Gain Minor Slayer at all times, increasing your damage done to Dungeon and Trial Monsters by 5%.
4 items: Adds 1-129 Spell Damage
5 items: When you use an Ultimate ability, you and the closest 2 allies within 28 meters of you gain Major Slayer for 10 seconds, increasing your damage done to Dungeon and Trial Monsters by 15%.
The set consists of light armor and jewelry in all slots, as well as weapons and shields of all types.