BW Clerical Error [Legacy] (Legacy)

Rotlung Reanimators and Xathrid Necromancers are the core of this deck. Hanweir Militia Captains and Thraben Doomsayers provide human tokens which can either be sacrificed or used to chump block and then provide zombie tokens via the Reanimators and Necromancers.
The Dark Supplicants and Scion of Darkness provide some flavor and the option of an early game powerhouse to attack with.
The Doomed Necromancers and Hell's Caretaker provide a really cheap way of making zombies (sac DN and bring back DN from grave, repeat for as much mana as you want).
Zulaport Cutthroats provide free damage and HP whenever you sac a creature or they die in combat.
Thalia's lancers help you find Ayli and Kalitas and can be sac'd for zombies later. Ayli provides a sac engine that also provides HP. Kalitas provides more zombies and keeps the enemy from using their graveyard easily.
Any creature can be brought back directly to the battlefield with DN or Hell's Caretaker.
The Eldrazi Monuments provide huge value with +1/+1, flying, and indestructible to your whole army, plus you get so sac another human every turn, creating more zombies.
Endless Ranks of the Undead is just more free zombies.
Harsh Sustenance is a great finisher if your zombie army doesn't do the trick since you can just stock up on tokens and then deal X damage at once. These are also useful for removing powerful creatures.
Necromancer's Covenant or Whip of Erebos can be added from the sideboard if you really need lots of lifelink.
There are 61 cards because Scion of Darkness is going to be searched for anyways or cycled if he ends up in your hand.