Ashenmoor Cohort

This creature gets +1/+1 as long as you control another black creature.

Smoldering Butcher

Wither (This deals damage to creatures in the form of -1/-1 counters.)

Igneous Pouncer

Haste
Swampcycling {2}, mountaincycling {2} ({2}, Discard this card: Search your library for a Swamp or Mountain card, reveal it, put it into your hand, then shuffle.)

Ashenmoor Liege

Other black creatures you control get +1/+1.
Other red creatures you control get +1/+1.
Whenever this creature becomes the target of a spell or ability an opponent controls, that player loses 4 life.

Kulrath Knight

Flying
Wither (This deals damage to creatures in the form of -1/-1 counters.)
Creatures your opponents control with counters on them can't attack or block.

Emberstrike Duo

Whenever you cast a black spell, this creature gets +1/+1 until end of turn.
Whenever you cast a red spell, this creature gains first strike until end of turn.

Spiteflame Witch

Corrosive Mentor

Black creatures you control have wither. (They deal damage to creatures in the form of -1/-1 counters.)

Ashling, the Extinguisher

Whenever Ashling deals combat damage to a player, choose target creature that player controls. The player sacrifices that creature.

Crowd of Cinders

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
Crowd of Cinders's power and toughness are each equal to the number of black permanents you control.

Necroskitter

Wither (This deals damage to creatures in the form of -1/-1 counters.)
Whenever a creature an opponent controls with a -1/-1 counter on it dies, you may return that card to the battlefield under your control.

Death Pits of Rath

Whenever a creature is dealt damage, destroy it. It can't be regenerated.

Maha, Its Feathers Night

Flying, trample
Ward—Discard a card.
Creatures your opponents control have base toughness 1.

Smolder Initiate

Whenever a player casts a black spell, you may pay {1}. If you do, target player loses 1 life.