The God capes are rewards from the Mage Arena minigame. To receive a cape, the player must win the minigame by defeating Kolodion in his four guises, then speak to him, step through the nearby sparkling pool, and finally pray at the statue of the god of a player's choice: Saradomin, Guthix, or Zamorak. Upon praying at a god's statue, the god's cape will appear next to the player and can be picked up.
The three types of god capes are:
The god capes, along with the appropriate God staves, were required to cast the spell Charge, which enabled the player to hit up to 50% higher with the appropriate God spell. Charge was eliminated with the Evolution of Combat update.
When dropped, a god cape is instantly destroyed without warning, as its respective god reclaims the cape when it touches the ground. Each of the capes only have a high alchemy value of 60 coins. If a player dies, their cape will not be kept on death.
Once lost, a player can get a new cape by once again praying at the statue of its god. (Kolodion does not have to be fought again.) If you want to avoid this, it may be advisable to select it as one of the three kept items, when there is little doubt of getting back to the gravestone in time.
God capes can be stored on the cape rack in your POH but only one can be owned at a time. To change between capes, the player must drop the current cape, which makes it disappear, and then pray at the statue of the god whose cape the player wants. Note that the game doesn't consider a cape stored in one's house to be "dropped," and will refuse to grant a new cape.
The same applies to god capes stored in the keepsake box after using a cape on the keepsake key. Even if you put a god cape in your keepsake box, you will not be able to retrieve a second one, from the same god or from a different one.
The god capes require a Magic level of 60.