2 items: Adds 3-129 Spell Damage
3 items: Gain Minor Slayer at all times, increasing your damage done to Dungeon, Trial, and Arena Monsters by 5%.
4 items: Adds 25-1096 Maximum Magicka
5 items: Dealing direct damage with a single target attack creates a ring of fire beneath you for 10 seconds. This effect can occur once every 10 seconds. Standing in the ring grants you a stack of Siroria's Boon for 5 seconds. Each stack increases your Spell Damage by 52. 10 stacks max.
The set consists of light armor and jewelry in all slots, as well as weapons and shields of all types.