Credit to AhornDelfin and their deck,
Expedition Armory, for giving me a skeleton for this. This deck is performing pretty darn well for me in expedition.
Blazing Salvo,
Creation Chant,
Pillar of Progress,
Dragon Forge,
Conspicuous Traveler,
Naoki, Valiant Warrior and
Shen-Ra Speaks are the heart of this deck, and should be 4-ofs no matter what.
Beyond that, there are various roleplayers this deck wants. In my opinion,
Ageworn Vestige and
Starsteel Daisho need to be at least 2-ofs, and
Hammer of Glory needs to be at least a 1-of. They all perform key functions to control a game.
Strange Blacksmith should also probably be at least a 2-of, providing game-winning weapon recursion.
That leaves 12 flex spots, which I have filled with
Amber Acolyte,
Xulta Arcanum,
Nahid's Distillation and a few extra weapons. Yes, I do think Xulta Arcanum might be flex in this build. While it does help stabilize you late, it doesn't do much to help you set up your relic weapon recursion loop beyond drawing, and that's your usual wincon.
I strongly suspect this deck would be substantially improved with 4x
Kato, Arena Herald, but I don't have the stone to craft him yet.
Sideboard filled with various cards that I've experimented with or think might be good in this shell.
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UPDATE: Cut Nahid's Distillation and one Strange Blacksmith (Nahid's doesn't contribute to the game plan ultimately and 4 Blacksmiths is a little awkward early before any weapons are in the void) and added 4
Jadehorns, which are performing extremely well for me. I think the deck has the right balance of board presence right now, all that's left is tweaking some of the flex slots. Hammer of Glory might need to be a 4-of, it's useful in several matchups. Got into the top 30 with this variant.
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UPDATE 2: Cut Xulta Arcanum, which was a dead card far too often, with Nahid's Distillation. With the number of units in this shell, it's not hard to trigger Nahid's on 4 or 5, which helps refill your hand and set up your relic strategy. Also, broke into the top 10.