Capes are a piece of equipment which can be worn on characters' backs for cosmetic purposes in addition to a slight statistical advantage.
Basic capes were available in both free-to-play and pay-to-play RuneScape Classic. They are commonly used for clan identification, especially in the Wilderness. Basic capes can be dyed in a variety of colours, and can be obtained in various ways. For more information, see their specific pages.
After the completion of the Legend's Quest, members can wear the Cape of legends, which provides a greater armour bonus than the standard capes, and come in an unique white colour.
God capes are obtained through the Mage Arena game, and are commonly used by mages in addition to a God spell, providing a considerable magic bonus.