When equipped with Evil Spell:

Increases damage of Flame Trap and Solid Trap by 20%.
Increases damage of Swift Trap and Deep Blind Trap by 40%.
Increases physical damage against enemies of every element by 20%.
Decreases variable cast time by 5%.

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

increases Flame Trap and Solid Trap damage by 20%,
increases Swift Trap and Deep Blind Trap damage by 40%,
increases physical damage against all property enemies by 20%,
reduces variable casting time by 5%.