{2}, {T}: Add {B} for each Swamp you control.

All Nightmares get +1/+1.

{B}{B}{B}, Pay 3 life: Put target creature card from a graveyard onto the battlefield under your control. That creature is black and is a Nightmare in addition to its other creature types.

When Chainer, Dementia Master leaves the battlefield, exile all Nightmares.

Enchant creature card in a graveyard

When Dance of the Dead enters the battlefield, if it's on the battlefield, it loses "enchant creature card in a graveyard" and gains "enchant creature put onto the battlefield with Dance of the Dead." Put enchanted creature card onto the battlefield tapped under your control and attach Dance of the Dead to it. When Dance of the Dead leaves the battlefield, that creature's controller sacrifices it.

Enchanted creature gets +1/+1 and doesn't untap during its controller's untap step.

At the beginning of the upkeep of enchanted creature's controller, that player may pay {1}{B}. If the player does, untap that creature.

{T}: Target creature gains shadow until end of turn. (It can block or be blocked by only creatures with shadow.)

{X}, {T}: Target opponent mills a card, then repeats this process until a creature card or X cards have been put into their graveyard this way, whichever comes first. If one or more creature cards were put into that graveyard this way, sacrifice Helm of Obedience and put one of them onto the battlefield under your control. X can't be 0.

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)

Flying

At the beginning of your end step, each opponent discards a card.

{1}{B}, Sacrifice an artifact: Target creature gets -2/-2 until end of turn.

At the beginning of your upkeep, you draw a card and you lose 1 life.

At the beginning of your upkeep, each opponent loses 1 life. You gain life equal to the life lost this way.

Whenever an opponent draws a card, Underworld Dreams deals 1 damage to that player.

{1}: The next time you would draw a card this turn, each opponent discards a card instead.