Teysa, Orzhov Scion is an inexpensive and versatile commander who can provide an immense amount of value for a deck built around sacrifice engines and black token generators. Being able to Unmake something for the price of a few tokens grants enormous utility and control potential - nothing feels better than blowing away a Prophet of Kruphix before it has a chance to untap anything, or keeping your opponents from casting key creatures for fear they won't live long enough be of any use.
This deck is built around Teysa and her combo with Darkest Hour. As all potential components of the combo are very cheap to cast, few cards in the deck cost more than six total mana. As such, the deck can combo out very fast and easily recovers from boardwipes - often with leftover tokens to start again. Keeping the curve low and abusing symmetrical effects like Grave Pact and Retribution of the Meek also keeps the deck from being overrun by ramping and big creature strategies (hi, Green!).
That said, the deck is constructed so that you don't need Darkest Hour to win - after all, it'd be a bit silly to rely totally on a single card. Cathars' Crusade, Maw of the Obzedat and Mirror Entity can make your tokens truly enormous, and Blood Artist is capable of draining at least one player to death without the combo in play (a different combo to Darkest Hour, like Reveillark/Karmic Guide, works just as well), and Debt to the Deathless is surprisingly easy to cast for lethal with all the mana generation you have (Nykthos, Shrine to Nyx, Urborg/Coffers and Ashnod's Altar all play star roles here). Smokestack is a classic wincon that will make a horrible mess out of players that cannot keep up with the cost. Use your removal aggressively, and you should be on your way!
The Combo
Darkest Hour + Teysa, Orzhov Scion + Any Free Sac Outlet + Any Other Creature = an infinite amount of whatever the sac outlet gives you.
Here's how it works. Teysa, Orzhov Scion gives you a white Spirit token whenever another black creature you control dies. Darkest Hour makes all creatures black. The Spirit tokens given by Teysa will thus turn black as soon as they hit the field, meaning you can repeatedly sac your tokens and get a replacement each time!
Now I know what you might be thinking - yeah, it's basically a four-card combo. Thankfully, three of those cards are very easy to access in the deck. Teysa, obviously, is your commander and thus usually available to you. The deck runs multiple sac outlets that work with the combo, and the deck is replete with creatures, many of which are token generators themselves. Darkest Hour is the hardest card to find, but with several relevant tutors and many ways to draw cards, you shouldn't have many problems locating it.
Comboing out with any sac outlet and Blood Artist on the board will also win you the game. Grave Pact, Dictate of Erebos and Martyr's Bond will also empty the board of other threats for you, so even if the combo doesn't end it all, you can still do a horrendous amount of damage to the board.
Critical Cards
Academy Rector - being able to pull any enchantment out for free, at instant speed if you keep her on the board with a sac outlet, is fantastic value. Whatever you need, you grab!
Bloodghast, Nether Traitor and Reassembling Skeleton - these guys are great sac fodder. Each can recur themselves at different times and for different costs, are black and so grant you tokens, and work well with Grave Pact effects. Break the synergy!
Debt to the Deathless - that art! That flavour! That it's better than Exsanguinate if you spend seven or more total mana on it! If you find yourself with not much to do, but with lots of mana to do it with, this card can be your ticket to a surprise win. Loves the two mana Altars, of course.
Elspeth, Sun's Champion - every mode is relevant! That's hard to find on a planeswalker in Commander. Blow up big stuff or make some fuel for your token fire, and if you luck into her ultimate, you can go on the offensive.
Nim Deathmantle - Nice to bring something straight back if you have the mana. Gives infinite reanimation with Ashnod's Altar if you can create one token when the reanimating creature dies, and infinite colourless mana if you get more than one.
Meekstone and Retribution of the Meek - big (heh) reasons why this deck runs few large threats. This deck is all about asymmetrical effects, and with Teysa's removal, Grave Pact effects, and only a handful of our own creatures above the power thresholds, these cards represent some of the best board control we could hope for.
Requiem Angel - the closest thing we have to a second Teysa. She can't combo like Teysa can due to the non-Spirit clause, but she can grant tokens where Teysa cannot, such as your mono-white creatures and Soldier tokens. Try to have both out and make it rain Spirits!
Sengir Autocrat - who would have thought that one of the best token generators in the deck would be some junk from Homelands? Four black bodies for 4 turns into four more white bodies with Teysa, and he's easy to reanimate too.
Skullclamp - in many ways one of the best cards in the deck. A non-free 'sac outlet' for your 1/1 tokens that basically makes all other draw cards redundant. If you pull Stoneforge Mystic or Enlightened Tutor, or even one of the straight tutors, you probably want this first.
Smokestack - ahhh, old-school! A win condition all on its own, make sure you have enough token generators to absorb the upkeep. Remember to stack the triggers so you sac before you put the counter on! At the very least, it demands removal that might be spent on something more critical.
Sorin, Lord of Innistrad - not as exciting (read: hate-inducing) as his Zendikar incarnation, but he's got great utility (and is much cheaper too!). Getting a black token every turn is really nice, and he's not likely to be a priority target.
Weathered Wayfarer - I really want to see this card played in more decks. A repeatable land tutor on a creature? Urborg, Tomb of Yawgmoth into Cabal Coffers into Nykthos, Shrine to Nyx is usually the best plan, but if you need colour fixing or a utility land by all means grab that first.
Xiahou Dun, the One-Eyed - Holy crap! Pull any black card back to your hand, on a creature? He is nuts, and a fantastic Commander himself. He's an ideal reanimation target with enormous utility - you could bring back Darkest Hour, set up a second Debt to the Deathless, or just pull back a card you desperately need a second time.
This deck is cribbed mostly from an MTG Salvation primer - but with the addition of the primary combo, as well as my own play-style and meta tweaks.
