The King of Thieves. This Boss is the poster child of, and is set to appear in, Boss Monster: The Next Level.
Porkus' Level Up Ability is interesting. It allows a player to remove a Hero they have killed from the game in order to take another Hero from the Hero Deck to replace the Hero they just removed. Essentially, the ability, in a way, reflects this Boss' title, as this gives the player a chance to steal a Hero from an opponent that the player with Porkus would not have ordinarily gotten with whatever rooms that they had in their dungeon.
Example: A player with Porkus has no Mage Rooms in their dungeon, while an opponent has plenty of Mage Rooms. The player with Porkus can activate his ability to discard a kind of Hero (say a Thief) that the other player may not be able to get as easily. The Porkus player can than go through the Hero Deck, and kill a Mage Hero that they would have otherwise not have gotten, thus stealing a potential Soul from the other player.
In other words, a slightly more complicated Seducia, in a way.
Porkus appears as a green, flying version of Ganon, a pig monster and the main antagonist from many of the early Legend of Zelda games. The King of Thieves comes from the Legend of Zelda: Ocarina of Time, during a scene when the young Princess Zelda tells the young Link that her father is speaking with the Gerudo King of Thieves, Ganondorf, an incarnation of the monster Ganon in the Legend of Zelda series.
Porkus's green skin is also another reference to Ganondorf, as in some games, Ganondorf is seen to have greenish-colored skin.
Porkus appears as the poster child of Boss Monster: The Next Level. He also appears on the cover of the Limited Edition Box, which features Porkus in a jumping pose similar to Mario, while holding one of the Brothers from the holofoil version of The Brothers Hero card.