Overview:

This mono-black deck leverages Zenos yae Galvus // Shinryu, Transcendent Rival as a board-control commander and win-condition enabler. The primary strategy revolves around deploying -1/-1 counters en masse via cards like Harbinger of Night, Midnight Banshee, and proliferate engines (Contagion Clasp, Yawgmoth, Thran Physician), crippling opponents' creatures while enabling death triggers. Zenos accelerates this by forcing a "duel" that weakens other creatures by -2/-2, priming the board for counter placement or wipe effects. Secondary win conditions include life drain (Gray Merchant of Asphodel, Vein Ripper), treasure victory (Revel in Riches), and Shinryu's alternate win-con against a targeted player. The commander acts as both a board reset and a lategame finisher, though the strategy functions semi-independently of him.

Primer:

Core Strategy Execution:

1. Early Setup (Turns 1-4): Prioritize ramp (Sol Ring, Crypt Ghast, Cabal Coffers + Urborg, Tomb of Yawgmoth) and card advantage engines (Phyrexian Arena, Black Market Connections). Deploy early counter sources like Soul Snuffers or Spitting Dilophosaurus. Protect key pieces with Lightning Greaves/Swiftfoot Boots.
2. Board Control (Turns 3-7): Cast Zenos to force a -2/-2 "duel," weakening the board for follow-up counter synergies. Use targeted removal (Dismember, Tragic Slip) or asymmetric wipes (Massacre Girl, Toxic Deluge) to clear threats. Activate proliferate engines (Contagion Clasp, Karn's Bastion) to spread counters. Leverage Nest of Scarabs and Blowfly Infestation to generate tokens or chain counters.
3. Win Condition Execution (Turns 6+):
   • Counter Overwhelm: Use mass counter spells (Black Sun's Zenith, The Meathook Massacre) or proliferate to wipe boards. Reanimate threats with Necroskitter or Virtue of Persistence.
   • Life Drain: Amplify death triggers with Drivnod, Carnage Dominus and drain via Gray Merchant of Asphodel, Vein Ripper, or Bontu's Monument.
   • Treasure Win: Generate treasures via Grim Hireling or Revel in Riches; protect until upkeep.
   • Shinryu Win: Eliminate Zenos' "chosen" opponent via focused drain/damage to trigger Shinryu's win condition.

Mulligan Priorities:

• Keep hands with 3+ lands, including at least one ramp source (e.g., Sol Ring, Arcane Signet) or land tutor (e.g., Cabal Coffers + Urborg).
• Prioritize early interaction (Dismember, Feed the Swarm) or a counter engine (Harbinger of Night, Yawgmoth).
• Ensure access to card draw (Phyrexian Arena, Black Market Connections) or a value piece (Black Market).
• Avoid hands lacking board impact before turn 4.

Key Tips:

• Maximize Proliferate: Use Yawgmoth, Thran Physician to sacrifice tokens (from Nest of Scarabs) for card draw and counter spreading. Contagion Engine doubles proliferate for devastating turns.
• Synergize Wipes: Cast Massacre Wurm after placing counters for massive life loss. Decree of Pain cycles for a board-shrinking effect early.
• Protect Engines: Shield Night of Souls' Betrayal, Ascendant Evincar, or Crumbling Ashes with boots/greaves. Phyrexian Tower sacrifices creatures doomed by counters for mana.
• Leverage Recursion: Necroskitter steals dying enemy creatures with counters. Virtue of Persistence reanimates key threats like Gray Merchant.

Weaknesses:

Critical

• Severely weak to enchantment/artifact removal targeting core engines (Night of Souls' Betrayal, Revel in Riches, Blowfly Infestation), which lack redundancy.
• Graveyard hate (Rest in Peace, Leyline of the Void) cripples recursion (Necroskitter, Virtue of Persistence, Black Sun's Twilight).
• Struggles against indestructible creatures or decks that go wide faster than counters can scale (e.g., token swarms).

Moderate

• Vulnerable to targeted land destruction disrupting Cabal Coffers/Urborg mana base.
• Limited stack interaction makes countermagic or instant-speed combos difficult to disrupt.
• High life payment costs (Toxic Deluge, K'rrik, Feed the Swarm) risk self-defeat in aggressive metas.

Minor

• Slow against decks with minimal creatures (e.g., spell-based combo).
• Commander tax on Zenos/Shinryu can be burdensome if removed repeatedly.

Most Important Cards:

• Yawgmoth, Thran Physician (Engine: Proliferate, draw, counter placement)
• Night of Souls' Betrayal (Global -1/-1, enables counter synergies)
• Urborg, Tomb of Yawgmoth + Cabal Coffers (Mana acceleration backbone)
• Gray Merchant of Asphodel (Primary life-drain finisher)
• Revel in Riches (Alternate win condition)
• Necroskitter (Creature theft engine)
• Contagion Engine (Mass proliferate, board softener)
• Massacre Wurm (Synergistic wipe + life loss)
• Black Market Connections (Card draw/treasure generation)
• Drivnod, Carnage Dominus (Amplifies death triggers)

Attribute Ratings:

Speed: 5/10

• Wins typically occur around turns 8-10 via gradual board control or life drain. Fastest wins involve explosive Gray Merchant/Revel in Riches turns with setup, but require significant mana/board state.

Resilience: 5/10

• Recursion (Necroskitter, Virtue of Persistence) and card draw provide recovery, but core enchantments/artifacts lack protection or redundancy, making the strategy fragile to targeted hate.

Consistency: 6/10

• Strong card draw (Phyrexian Arena, Black Market Connections) and tutors (Demonic Tutor implied but not listed) ensure access to key pieces, though some engines are unique.

Interaction: 6/10

• Efficient targeted removal (Dismember, Feed the Swarm) and board wipes (Toxic Deluge, Mutilate), but lacks countermagic and struggles with non-creature permanents beyond enchantments.

Rating Justification:

This deck executes a focused casual strategy with clear -1/-1 counter synergies and multiple win paths, but its speed is capped by setup requirements and reliance on sorcery-speed control. Resilience is moderate but falters against dedicated hate, placing it between optimized casual and focused tiers.

Power level: 4.5 - 5.0