Cards are items that are installed into equipment to provide beneficial effects to the player. Equipments with slots can be installed with a card. A maximum of 4 slots are available on weapons, and 1 slot for footgears, garments, accessories, armors, shields and headgears.
You can acquire cards in different ways:
- Most monsters in-game have a 0.01% chance of dropping their own card.
- Some usable items give cards:
- will create a random non-MVP card.
- give a random "mini-boss" card.
- give a random card from one of the six class sets.
- Trade for or buy one from a vending shop.
- Reward from Overlook Water Dungeon Quests.
By double-clicking the card, you can compound the card into a piece of equipment of your choice. The card does not disappear from your inventory until you install the card in a piece of equipment.
To install, the equipment must have a slot available for a card to go in. Cards only install into their own specific type of equipment category. When double-clicked, you are shown list of equipment you currently have that the card can be put in to. Right click the card to see what effect it gives, and where it can be installed.
To see if your equipment has a slot available for a card, simply mouse over the equipment in question. if it does, it'll appear with suffix  to . An example would be "Guard ", which means it has 1 slot for inserting a card. Some equipment can have slots added to them via Socket Enchant.
Many weapons (mainly weapons that can also be bought from NPC shops) have multiple variants with different numbers of slots. For example, "Blade " is store-bought, and "Blade " is dropped by monsters. If a piece of equipment is destroyed because you failed when you tried to upgrade it, the equipment and all of the installed cards will be destroyed. If a piece of equipment is damaged in battle, it will not harm the cards.
- Main article: Card Sets
Certain bonuses are granted when using various combinations of cards at the same time. Most cards in sets are inserted into different pieces of equipment. Set bonus, whether from equipment, card or enchant are only applied once, even if the player have multiple instances of it.
- Main article: Card Desocketing
Card desocketing is a way for players to remove slotted cards from their equipment.
|Items in Ragnarok Online|
|Equipment||Armors • Headgears • Weapons (Weapon Materials) • Shields • Garments • Footgear • Accessories • Equipment Sets • Skill Equipment • Shadow Equipment|
|Cards||Card Reference • Card Sets|
|Consumables||Healing Items (Restoration Calculation) • ASPD Potion • Taming Items|
|Item Mixing||Juice Ingredients • Potion Ingredients • Dye Ingredients • Tame Ingredients • Headgear Ingredients (Headgear Quests) • Cute Pet Equipment • Counteragent and Mixture Quest|
|Miscellaneous||Quest Items • Autocast|