When equipped with Good Spell:

Increases damage of Abyss Dagger by 20%.
Increases damage of Deft Stab by 40%.
Increases physical damage against enemies of every element by 20%.
ASPD +5% (Decreases after attack delay by 5%).

[iRO Description]
Set Bonus:
Good Spell
Good Vigor (Abyss Chaser)

increases Abyss Dagger damage by 20%,
increases Deft Stab damage by 40%,
increases physical damage against all property enemies by 20%,
ASPD +5%.