The 20th anniversary Diablo tributes continue to roll out, with Hearthstone's version now appearing as this week's Tavern Brawl.

Players will take on Diablo's Dark Wanderer, who will reveal numerous secrets from his deck. His hero power is "Summon a random Imp." Triggering his Secrets appears to open an "Enigmatic Portal" that transfers the player to a battle against The Cow King. Bovine-related hijinks ensue. The two minions that can counter-act Secrets, Eater of Secrets and Kezan Mystic, are not usable in the Brawl.

Winning the match, whether against the Dark Wanderer or the Cow King, will grant a new "Secret Level" card back.

The Diablo cards, secrets and spells are as follows (via Hearthhead):

• Weapon Rack - Deathrattle: Current turn player gains a random weapon. (Weapon)
• Discarded Armor - Deathrattle: Current turn player gains 5 armor.
• Chest of Gold! - Deathrattle: Current turn player gains gold!
• Diabolical Powers - Summon a random Imp. (Hero Power) - The Dark Wanderer
• So Many... - Whenever a Hell Bovine Dies, draw a card. (Hero Power) - The Cow King
• Hell Bovine  - Deathrattle: Place a copy of this card in your deck.
• Guardian - At end of your turn, deal 2 damage to the enemies opposite this minion.
• Hell Bovine Champion - Deathrattle: Current turn player gains a random weapon.
• Visions of the Assassin - Secret: When your opponent summons a minion with Stealth, All minions equip a dagger.
• Visions of the Barbarian - Secret: When your opponent summons a minion with Charge, THUNDER FURY!
• Visions of Hate - Secret: When both heroes have 15 or less Health, BRAWL!
• Visions of the Crusader - Secret: When your opponent summons a minion with Taunt, change all minions' attacks to 1. 
• Visions of Valor - Secret: When your opponent summons a Legendary minion, give all minions Windfury.
• Visions of Fate - Secret: When your opponent takes lethal damage... save him.
• Visions of the Amazon - Secret: When your opponent summons a minion with Battlecry, Summon a Mirror Image for both players.
• Visions of the Sorcerer - Secret: When your opponent summons a minion with Spell Damage, Summon 2 Guardians.
• Visions of the Necromancer - Secret: When your opponent summons a minion with Deathrattle, destroy it.
• Visions of Knowledge - Secret: When your opponent's hand has 9 or more cards, reduce the cost of all cards in both hands to (1).
• Lightning - Deal 3 damage. (Spell)
• Summon Guardians - Summon two 2/4 Guardians. (Spell)
• Moo.. - Summon 3 Hell Bovines. Give all Hell Bovines Taunt. (Spell)
• The Portal Opens - Through the Nether and into... (Spell)
• Stampede - Summon 2 Hell Bovines. Give all Hell Bovines Charge. (Spell)
• The Cow King (Hero)
• Twisting Nether? - "This doesn't look like Twisting Nether..." (Spell)
• Enigmatic Portal - At the start of next turn, your hero is transformed and sucked through the Twisting Nether. (Minion) - The Dark Wanderer

Blizzard is planning other events in its games for the anniversary, with World of Warcraft now having a cow level for a limited time. The Diablo 3 patch 2.4.3 coming soon will also add the Darkening of Tristram throwback tribute levels.