This deck is not super competitive, but it is more than capable of winning its share of games. I also don’t know who named this deck or who originally created it, but this list and what I’ve seen comes from Jeff Hoogland’s stream. It looks like a total blast to play, and the games are effectively over on turn 1 every single time. The Spanish Inquisition aims to kill on the first turn, and when it fizzles or the opponent has any interaction, it tends to lose on the first turn!
This deck only runs 2 total lands. There’s a single Bayou used to cast your spells, and there’s a Dryad Arbor that doubles as a land and a creature. You have Land Grants to help find your lands, which serve as a mana source and are important for making sure that there are no more lands in your library.
One of the primary win conditions is Goblin Charbelcher. Belcher requires you to have 7 mana, but you can spread that out over multiple turns. If you were able to remove both lands from your deck, you get to deal 40+ damage and win on the spot. If not, you’re gambling that you deal enough damage through an activation or you’re going to need to find enough mana to try again. Your other win condition is through casting enough spells to Tendrils of Agony your opponent out.
In a deck with only two lands, and only a single land you actually plan to tap for mana, you’re going to need some ways to get started. This comes from both Elvish Spirit Guide and Simian Spirit Guide, as well as Lotus Petal and Chrome Mox. These are the best ways to get from 0 to 1 mana and start the train.
Once there, you have a handful of ritual effects. Dark Ritual adds the most mana for the smallest investment, and Cabal Ritual can get you a big mana boost once threshold is online. You also have the full playset of Culling the Weak, which is the real reason Dryad Arbor makes the cut. The extra land in your deck is a big cost when trying to win with Goblin Charbelcher, but a bunch of extra Rituals in Culling the Weak makes it all worth it.
Summoner’s Pact serves as a way to get started as it can go find an Elvish Spirit Guide—but it has a few other uses. Getting Dryad Arbor can clear a land from your deck to go off, or Wild Cantor can filter your mana from green or red into black to start casting Rituals. You also have a Manamorphose for this effect when needed. This deck requires a lot of black mana to go off in most instances, and this is a great way to get there. You also have a Skullwinder and Skyshroud Cutter to get off the Pact, but I honestly just don’t get it. I can certainly imagine situations where they’re useful, but I would never put them in my deck.
Once you get off a Ritual (or more Rituals), you have a bunch of ways to draw four cards. Infernal Contract and Cruel Bargain both make you cash in your life total in exchange for a bunch more cards. This is a great way to find more mana or a win condition in order to win the game, and is critical for getting to 10 spells for a Tendrils to end it. There are also many games where you’ll fire off one of these draw-4s, brick off, and concede on the spot!
Lion’s Eye Diamond is the best way to get a bunch of mana, but it does nothing to get you started. Instead, it’s there to sacrifice in response to a draw-4 so that you have mana after it resolves to activate a Charbelcher that’s in play, or to combo with Infernal Tutor. Tutor can be cast and responded to by sacrificing Lion’s Eye. This will discard your hand, gain 3 mana, and turn Infernal Tutor into a Demonic Tutor that can find anything you need.
While this may not be the most competitive deck in Legacy, it does play out well for those who love to solve puzzles and put the pieces together to find tricky wins. You almost never touch the sideboard when not playing against blue decks, but since a single counterspell effect (or discard effect, or Sphere of Resistance, or Chalice of the Void, or Thalia, etc.) often ends the game, it can be useful when you need it!