Dark attack attribute increases by 5 when bestowed on a weapon. Holy defense attribute increases by 6 when bestowed on an armor. Attribute Crystals can be used up to attribute level 6. Additionally, a maximum of three types of Elemental defense attribute can be bestowed, and one type of Elemental attack attribute. Opposite attributes cannot be bestowed together. Yin in the Town of Aden and Yang in the Town of Rune exchange the crystals for Dark Jewel.