Grow one Blade all fight, then double it on the boss. Slow, but it kills.
Data from build 23811903, updated

The Regent
Heir to the Throne of Stars. Wields cosmic powers but his minions do the work.
Every Forge card adds damage to one Sovereign Blade, and the Blade Retains between turns. Furnace and Fencing Manual keep it growing while you block, then Conqueror and Sword Sage turn the swing into a boss-killing hit. The Blade hits one enemy until you find Seeking Edge, so crowds are the weak spot. It starts slow. Block hard in the meantime.
Fencing ManualCommonForge 10 at the start of every combat. The Blade is already worth swinging on turn one.
Dolly's MirrorShopCopy Furnace or Summon Forth. A second engine piece is worth more than any filler.
Ice CreamRareEnergy carries over between turns, so a turn spent blocking funds the 2 Energy Blade swing later.
1FurnaceUncommon PowerAt the start of your turn, Forge 5.Forge 5 at the start of every turn. The passive growth the whole plan runs on.
1Summon ForthUncommon SkillPut Sovereign Blade into your Hand from anywhere. Forge 8.Puts the Blade in your hand from anywhere and Forges 8. It means you never lose track of your payoff.
1ConquerorUncommon SkillForge 3. Sovereign Blade deals double damage to the enemy this turn.Forge 3, and the Blade deals double damage to one enemy for the rest of the turn. Play it right before the swing.
2Sword SageRare PowerSovereign Blade gains Replay 1.Replay 1 on the Blade, so every swing plays twice. Mark the target with Conqueror first, because the mark lasts all turn.Take these on sight. The build doesn't work without them.
Strong once the core is in. Take them over anything below.
Fine until something better shows up. First to go when a shop offers removal.
Does little in this deck. Skip the reward and keep the deck thin.
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Open the card tier list