Overview:

This mono-black Rat tribal deck helmed by Marrow-Gnawer focuses on swarming with Rat Colony synergies and leveraging sacrifice outlets for explosive token generation. The primary win conditions involve overwhelming combat damage amplified by tribal lords (Ashcoat of the Shadow Swarm, Karumonix, the Rat King) or infinite loops with Thornbite Staff + Ashnod's Altar/Phyrexian Altar to create infinite Rats/mana. Secondary stax elements (Contamination, Grave Pact) and resilient finishers like Eldrazi Monument provide alternative paths. Marrow-Gnawer is critical as both a token generator and combo enabler, though the deck can function temporarily without it thanks to redundancy in Rat payoffs.

Primer:

Core Strategy Execution:

1. Early Setup (Turns 1-3):
   • Deploy fast mana (Dark Ritual, Culling the Weak, Mana Vault) to accelerate into Marrow-Gnawer or key artifacts.
   • Cast early Rats (Rat Colony, Lord Skitter, Sewer King) to build board presence.
   • Tutor for combo pieces (Thornbite Staff, Phyrexian Altar) or card engines (Necropotence, The One Ring).

2. Mid-Game Engine (Turns 4-6):

   • Activate Marrow-Gnawer’s ability with 5+ Rats to exponentially grow the board.
   • Equip Thornbite Staff to Marrow-Gnawer: Sacrifice 1 Rat → create X Rats → untap Marrow-Gnawer. Pair with Ashnod's Altar for infinite colorless mana or Phyrexian Altar for infinite black mana/Rats.
   • Deploy stax pieces (Contamination, Dictate of Erebos) to disrupt opponents while building toward a finisher.

3. Win Conditions:

   • Combat Overrun: Use Ashcoat of the Shadow Swarm (potentially +X/+X = 20+) or Eldrazi Monument for lethal swings.
   • Infinite Mana/Combo: Channel infinite mana into Bolas's Citadel activations, Walking Ballista (if added), or Exsanguinate-like effects (not in list – a potential gap).
   • Stax Lock: Contamination + token generation forces opponents to rely on Marrow-Gnawer’s black mana.

Mulligan Priorities:

• Keep hands with 2-3 lands, preferably including Swarmyard or Cavern of Souls.
• Prioritize fast mana (Dark Ritual, Sol Ring) or early Rat generators (Lord Skitter).
• Avoid hands lacking ramp or a critical mass of Rats without tutors.

Key Tips:

• Sacrifice Rats to Skullclamp for explosive card draw.
• Use Phyrexian Tower/Ashnod's Altar to fuel Bolas's Citadel or Eldrazi Monument.
• Emergence Zone enables surprise deployment of Grave Pact or Dictate of Erebos.

Weaknesses:

Critical

• Commander-dependent: Repeated removal of Marrow-Gnawer cripples token generation and combo potential.
• No graveyard recursion for artifacts (e.g., Buried Ruin is lone recovery), making combo pieces vulnerable.
• Lacks answers to enchantments beyond Feed the Swarm (only 1 copy).

Moderate

• Weak to board wipes: Relies on Eldrazi Monument for indestructible, but sacrifices creatures every turn.
• Struggles against Rest in Peace/Leyline of the Void, shutting off Volrath's Stronghold and Ashcoat’s recursion.

Minor

• Limited interaction for noncreature permanents (e.g., planeswalkers, artifacts).
• Cursed Totem nullifies Marrow-Gnawer’s tap ability.

Most Important Cards:

• Marrow-Gnawer (Token generation/combo engine)
• Thornbite Staff (Infinite loop enabler)
• Ashnod's Altar (Mana/combo piece)
• Ashcoat of the Shadow Swarm (Combat finisher)
• Necropotence (Card advantage)
• Contamination (Stax lock)
• Phyrexian Altar (Mana/combo redundancy)
• Demonic Tutor (Tutoring critical pieces)
• Eldrazi Monument (Evasion/resilience)
• Rat Colony (Core tribal synergy)

Attribute Ratings:

Speed: 6/10

• Can threaten T4-5 wins with ideal draws (fast mana → Marrow-Gnawer + Thornbite Staff), but inconsistent without tutors.

Resilience: 5/10

• Vulnerable to commander removal and artifact hate, but recursion (Volrath's Stronghold, Buried Ruin) and protection (Swarmyard) provide partial recovery.

Consistency: 7/10

• 10+ tutors and strong card draw (Necropotence, Phyrexian Arena) ensure access to key pieces.

Interaction: 5/10

• Efficient targeted removal (Cut Down, Snuff Out) and board wipes (Damnation), but lacks countermagic and broad noncreature answers.

Rating Justification:

This deck operates at a Focused power level, capable of T6-7 wins via combos or combat with strong tutoring and redundancy. However, its reliance on the commander and vulnerability to common interaction (artifact/enchantment removal) caps its resilience, preventing it from reaching optimized tiers.

Power level: 6.0 - 6.5