The card with the Secret ability is played face-down, with its effect triggering when a certain condition is fulfilled. Players can keep track of how many secrets they have in play, as they appear above the hero as "?". Secrets are considered spells and can be countered through the use of abilities like or copied via . Secrets are limited to Mage, Hunter, and Paladin. During alpha, Rogue also had secrets to round out the classes with stealth/camouflage/invisibility, but the class had too many themes, while Paladin didn't have enough, so secrets were given to Paladin instead.
can destroy all enemy secrets. can also destroy all enemy secrets except Counterspell and will be copied by . and put one of each of the remaining secrets in the deck in play. draws a secret from the deck. discovers a paladin secret. puts a random hunter secret in play when a secret is played. costs less for each secret played. and make the next secret played cost no mana. makes secrets cost no mana. , , and work best with secrets in play.
- Since they are considered spells, they are affected by Spell Damage.
- Duplicate secrets cannot be in play by the same player.
- Multiple secrets may trigger at once, but trigger in the order in which they were played.
- A player may only have five secrets in play at a time.
- If a minion has a battlecry at the time it is played, the battlecry will trigger, then the secret.
Below is a list of all cards with the secret mechanic.
- Note: For the purposes of this list, only collectible cards are listed.