Be'lakor, the Dark Master

Flying
Prince of Chaos — When Be'lakor, the Dark Master enters, you draw X cards and you lose X life, where X is the number of Demons you control.
Lord of Torment — Whenever another Demon you control enters, it deals damage equal to its power to any target.

Demon of Catastrophes

As an additional cost to cast this spell, sacrifice a creature.
Flying, trample

Bloodgift Demon

Flying
At the beginning of your upkeep, target player draws a card and loses 1 life.

Cancel

Kaervek the Merciless

Whenever an opponent casts a spell, Kaervek the Merciless deals damage equal to that spell's mana value to any target.

Demonic Tutor

Search your library for a card, put that card into your hand, then shuffle.

Sol Ring

Counterspell

Demon's Horn

Whenever a player casts a black spell, you may gain 1 life.

Demon's Grasp

Target creature gets -5/-5 until end of turn.