Magtheridon is a 4 Mana Cost Legendary Neutral Minion Demon card from the Ashes of Outland set!
Dormant. Battlecry: Summon three 1/3 enemy Warders. When they die, destroy all minions and awaken.
Flavor TextCame from another world to invade Outland and bend it to his will… only to be overthrown by an elf from another world who invaded Outland and bent it to his will.
Magtheridon Additional Information
You need to summo and kill ALL THREE Warders for the effect to go off. If your opponent has 5 or more minions and you don’t summon all three, it won’t be able to wake up. Similarly, if your opponent transforms one of the Warders (e.g. with Polymorph), it also won’t wake up. However, Silencing Warders does not stop Magtheridon from waking up. (Source)
Cards Relating to Magtheridon
Type: Minion - Cost: 1 - Attack: 1 - Health: 3
(Magtheridon will destroy all minions and awaken after 3 Warders die.)