When equipped with Evil Spell:

Increases damage of Soul Vulcan Strike by 20%.
Increases damage of Mystery Illusion by 40%.
Increases magical damage against enemies of every element by 20%.
Decreases variable cast time by 5%.

[iRO Description]
Set Bonus:
Evil Spell
Evil Vigor (Arch Mage)

increases Soul Vulcan Strike damage by 20%,
increases Mystery Illusion damage by 40%,
increases magical damage against all property enemies by 20%,
reduces variable casting time by 5%.