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 activate a synergy, you gain a shadow blessing that increases your Spell Damage by 10-448 or a lunar blessing that increases your Magicka Recovery by 10-448 for 30 seconds. You can only have one blessing active at a time.
The set consists of light armor and jewelry in all slots, as well as weapons and shields of all types.