Skill crystal

Monster Card is a rare drop from demons.

Appearance
Monster Cards are about the same size as Intelligence Cards. They also appear to be blank.

Description
Monster Cards are cards, that when fused to a piece of equipment, will bestow upon that equipment a skill that depends on what kind of Monster Card is used. Only a Master Smith can perform Monster Card Fusion. Monster Cards can only be identified using a Guild Temple. They first appeared in Web Novel Chapter 45.

Trivia

 * Monster Cards are very rare drops, as it seems that there aren't a lot of them in circulation; the only other way to get them is through auctions.
 * There are Monster Cards that are called high-ranked Monster Cards that can only be used when fused to an equipment together with a High Kobold Monster Card.
 * Most people believe that Monster Card Fusion relies on luck. This however is false as a Monster Card Fusion will always succeed as long as the item has an empty skill slot. If there are no more empty skill slots; the fusion will fail, the Monster Card will disappear, and the item will be reduced to its raw materials.
 * Michio uses Appraisal to tell if an item has an empty skill slot or not.