Hello and welcome, this is my budget mono red 12-post deck for legacy. Despite being easy on the wallet for such an expensive format and some admittedly very janky card choices on my part, this deck can really be quite powerful. This deck regularly wins games at my local store, but has not yet been able to go 4/0.
I believe that with a few bigger investments such as Candelabra of Tawnos (replacing Mind Stone), mono red 12-post could be competitively viable in legacy.
Game Plan
This deck is very simple and easy to play. It is a great introductory deck for players new to legacy transitioning from modern, as 12-post in legacy is similar to the tron archetype in modern.
Turn 1:
We are either playing Expedition Map or Amulet of Vigor. These cards increase the value and speed of our incremental mana base. ( Cloudpost Glimmerpost Vesuva Thespian's Stage )
Occasionally it may make more sense to play Lantern of Insight to avoid bad draws or Terrarion to fix for red mana in the absence of a mountain.
Turn 2:
We are are either playing Mind Stone or Credit Voucher. These cards quickly dig further into the deck and accelerate mana.
Occasionally we may have access to Etched Champion or Lodestone Golem on turn 2, in which case that is the preferable option.
Turn 3:
By this turn we should easily be producing 4-5 mana or more per turn, giving us access to Lodestone Golem, Nevinyrral's Disk, Etched Champion and Karn, Silver Golem. These cards prevent the opponent from winning on their next turn.
Occasionally it may make more sense to play Krark-Clan Ironworks in order to set up for Banefire a turn early, or Kuldotha Forgemaster in order to find either Krark-Clan Ironworks or Bosh, Iron Golem
Turn 4:
This should be the winning turn. If you've managed to deal any damage at all throughout the game, you should win with Bosh, Iron Golem, Flameblast Dragon or one of many red burn spells with X in their mana cost such as the title card Banefire.
Turn 5:
The deck runs 11 red mana sinks just in case our turn 4 win is shut down, we should have a second opportunity here.
Sideboard
Against delver or cephalid combo take out 2 copies of Glimmerpost and 2 copies of Earthquake in exchange for 4 copies of Red Elemental Blast
Against death and taxes take out Bosh, Iron Golem, Flameblast Dragon and 2 copies of Kuldotha Forgemaster in exchange for the most appropriate combination of Pithing Needle, Alpine Moon, Crumble to Dust or Swiftfoot Boots.
Against storm, reanimator or dredge take out 2 copies of Kuldotha Forgemaster, Flameblast Dragon and Nevinyrral's Disk in exchange for Nihil Spellbomb, Tormod's Crypt, Relic of Progenitus and Sentinel Totem. The reason for 4 different instances of grave hate is to avoid our opponent shutting it down with Pithing Needle.
Needed (but expensive) Upgrades
Thanks for reading!
