Massacre Girl 
Legendary Creature — Human Assassin · Duskmourn: House of Horror Commander
Menace
When Massacre Girl enters, each other creature gets -1/-1 until end of turn. Whenever a creature dies this turn, each creature other than Massacre Girl gets -1/-1 until end of turn.
Plays well with: Sacrifice, Value engine
Buy this card: TCGplayer · Cardmarket
Decklists on EDHREC View on Scryfall More Mono-Black commanders
📖 How to build Massacre Girl
Massacre Girl is a five-mana legendary black Assassin with menace. When she enters, each other creature gets -1/-1 until end of turn. Whenever a creature dies that turn, each creature other than her gets another -1/-1. One death can start a chain that shrinks the whole board, and she can then attack with menace, which requires two or more blockers.
Build around ways to make creatures die and to get her onto the battlefield. Blood Artist rewards creatures dying, and Feed the Swarm and Victimize can put that into motion. Toxic Deluge also kills creatures, which triggers her second ability. Tutors such as Demonic Tutor and Vampiric Tutor can find her, and Reanimate can return her from the graveyard to trigger her enter ability again. Dark Ritual can help her come down early.
Her effects hit every other creature, including your own, so she performs poorly on a wide board of small creatures you control. The -1/-1 lasts only until end of turn, so it only removes creatures with low toughness. Menace is her only evasion, and she offers no protection of her own beyond that.
Deck guide written with AI assistance based on the card's rules text.
🔗 Sacrifice synergy
$38.75
$1.59
$0.33
$15.78
$32.19
$0.45
$3.60
$1.71🧩 Top staples for this deck
✔️ Auto-includes (you probably already run these): Sol Ring, Command Tower, Arcane Signet, Exotic Orchard, Reliquary Tower, Swiftfoot Boots, Lightning Greaves, Path of Ancestry.
$8.06
$10.31
$62.61
—
$0.22
$3.07
$26.94
$51.50
$12.92$1.59$0.33
$3.49⚙️ Colorless all-stars
—
$5.89
$11.44
$105.01
$49.67
$33.79🪙 Budget picks (under $2€2)
$1.39$0.22$1.59$0.33
$0.41$0.45
$0.27
$1.95👑 Other Mono-Black commanders
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Mono-Black · $5.97Staples are based on how often cards are played in Commander overall (popularity data via Scryfall/EDHREC) and filtered to this commander's colors. Synergy picks match the commander's rules text.