ETB Creatures
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ETB/LTB creatures are the real bread and butter of the deck. Reusable effects that give you advantage in the current board state are valuable when you can use them two, or three, or four times in a game. Creatures that can sac themselves get extra bonus points.
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Puppeteer Clique - 5 Mana to bring back any creature from any graveyard TWICE!, also giving them haste in addition until the end of turn. This bad boy can go from harmless to chaotic in a matter of seconds!
Fleshbag Marauder - Unless you are playing Sigarda, Host of Herons, Fleshbag Marauder is an absolute All-Star in this deck. Everyone sacs a creature, but Fleshbag Marauder will always sac itself so its nicely in the graveyard to reuse again. With Chainer out, Fleshbag Marauder can reanimate a time or two and basically clear out the field, even with hexproof and shroud. Three plus mana open with Chainer out and Fleshbag Marauder in the graveyard will effect how your opponents play.
Xiahou Dun, the One-Eyed - This guy is amazing; he basically returns every non artifact in the deck to your hand. While that may not sound like much, using Demonic Tutor or Exsanguinate three or four times will really put you ahead. If you have good toys in your yard, Xiahou Dun, the One-Eyed is a great addition. He also nicely can sac himself making him all the more powerful in this deck.
Mindslicer - Mindslicer is so much fun. No card is better at getting a heap of cards in the graveyard as quickly. His effect is LTB, but that is usually not a big thing to deal with considering the number of sac outlets. The best part of this card is that it removes the potential for counterspells and kill spells, if only for a turn or two. A great card to kill right before going for that kokusho death loop to hopefully keep any hate away.
Solemn Simulacrum - Good old sad robot. Land ETB and Draw LTB. Pure Card advantage with ramp on the side. I'm never Sad to see the Sad Robot.
Kagemaro, First to Suffer - Facing down an Army? This guy is a repeatable Wrath of God on stick that can kindly sac itself for for one black mana. The size of his Wrath is variable, but none-the-less his potential is lethal. He can also serve as a decent beat stick if you do not need a wrath, assuming you have a decent hand size.
Slum Reaper - This card is de facto Fleshbag Marauder number two. While it does have a bigger body, costing one more mana does make it slightly worse than Fleshbag Marauder, but not by much. Once it gets going, watch out.
Bone Shredder - Reusable targeted removal for non-black, non-artifact creatures. Against the right decks this guy can clean house, over and over again. There are also occasions he's not so hot when you do face another black deck. He does have the added benefit of sacrificing himself during the next turn so he can be reused if a sac outlet is not available.
Duplicant - Some threats just refuse to die and when they do die they shuffle themselves back into the library so we can't play with them (looking at you Ulamog, Iona, Blightsteel, et al.). For the things that have no other answer there is Duplicant. Duplicant is also the only unconditional, targeted removal so he does double duty against other black decks.
Kokusho, the Evening Star - Kokpuffs is quite a few things. With enough mana and a sac outlet, she can kill your opponent outright. Even if you play her and she just dies, you will gain a good amount of life in the process. She's one of those cards your opponents don't want to kill so she can often ping through for that five damage more often than not. Generally speaking, its best to save playing or tutoring for Kokusho until later in the game when you are closer to going for a win so it doesn't get exiled somehow. Exiled Kokopuffs makes me a sad panda.
Massacre Wurm - The deck's anti-token tech (or anti Edric weenie tech). Deals two damage to all opponents' creatures and deals direct damage when their creatures die and all in a big body. He has a very fun line of play when combined with Living Death.
Rune-Scarred Demon - Tutoring is pretty powerful in this game. I like having the answer at any time or the ability to grab it. With this guy, I get a recurrable tutor on a 6/6 flying body. Reanimating him a few times will generally put you in a very good position.
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Non-ETB Creatures
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Even though a big focus is on ETB guys, All of the non ETB creatures have a high amount of value to what this deck wants to do.
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Blood Artist - Blood Artist gains life when creatures die. Lots of creatures die...Awesome!!!. Lets also not forget he can send that back at someone as damage too. Some games, this guy is an MVP.
Bloodghast/Reassembling Skeleton - These guys are all cheap self-reusable creatures that can be sacked to Skullclamp or in a pinch sacked to Braids, Cabal Minion.
Bloodline Keeper - He poops tokens and with Rings of Brighthearth, potentially a bunch. The flying takens make great blockers if needed. Given enough time out, he can become his own win condition. I've had a wrath played by an opponent solely to stop a flipped Keeper before.
Braids, Cabal Minion - Pure madness. You will lose friends when she's out. If you correctly time putting her out, you may very well win the game though. Braids is good at killing creatures, but is also known to take out lands, etc. You do have to be careful so that she does not backfire and force you to sacrifice too much. There is definitely a right time to play her, like after dropping Bitterblossom or Crucible of Worlds
Falkenrath Noble - Blood Artist number two. He's generally inferior since he costs twice as much, but he does have a semi-relevant flying body to make up for it.
Sangromancer - Sangromancer is easily the best life gaining tool in a deck that sorely needs life gain. She gains life when the deck does what its supposed to do: kill the opponent's creatures. Consequently her three life gain helps nullify Chainer's life cost if you are cycling say Fleshbag Marauder.
Geth, Lord of the Vault - Geth is one strong hombre in the late game phase. Geth is quite mana intensive, but once he gets going, your opponent will kill him or he can bury them. He can reanimate multiple creatures per turn and in a few turns can mill an opponent out as a secondary win condition.
Pawn of Ulamog - This card serves so many uses in this deck. Its one of the few 'combo pieces' that we actually run. It can make tokens to feed to Smokestack or it can generate mana to fuel some crazy plays. Its also nice in that it drops you tokens to play with after a wrath effect if you have creatures out.
Nirkana Revenant - She is a creature that kicks butts and takes names. She doubles the mana generation from your swamps and gets +1/+1 till the end of turn for each black mana spent. She serves as both mana ramp and hard beating win condition in one nice package. I'm never sad to see her and she generally has a lower threat value than most of the other cards.
Sheoldred, Whispering One - Quite possibly the strongest creature in the deck. I generally go out of my way to get her online at some point during the game. She acts like a combination of Braids, Cabal Minion and Chainer, Dementia Master on one body. I've had opponents scoop the moment she hit the table on more than one occasion when they had no answer. The longer she stays out, the more value you get from her, especially if you have strong creatures in your graveyard. She wins games.
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Draw/Tutors
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This deck works very much in a toolbox fashion with particular answers to certain board states. Card Draw and tutoring are crucial to having the answer you need in a timely manner.
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Vampiric Tutor - A one cost tutor. Probably the best option after Demonic Tutor although I've always been on the fence about putting cards on top of the library. At least its an instant so you can cast it on the end of an opponent's turn.
Scrollrack - Ever had a bad hand, and just wanted to get rid of it. Well good news! they mad a OP artifact called "ScrollRack", that can do that for you. 2 mana artifact with instant speed to get a brandnew hand for the cost of 1. I chose this over sensei's divining top because I thought it was more useful.
Expedition Map - This artifact was inserted in the deck for one purpose...Find Cabal Coffers!!! If Cabal Coffers has already been found, Urborg, Tomb of Yawgmoth, High Market or Deserted Temple are also great targets. Worst case, you can fetch yourself a Swamp. All in all a high value land tutor
Skullclamp - One of the most broken equipment ever printed makes a showing here. Bloodghast and Reassembling Skeleton are here mainly as cheap self-recurring dudes who insta-die to the clamp. Its also nice to equip the Skullclamp on Xiahou Dun, the One-Eyed before using his ability or Bitterblossom tokens.
Necropotence - Arguably the best draw card ever printed. It has a drawback, but it will get you 7 cards in your hand every turn. You do have to be careful so that it does not eat your life total away too far, but its acceleration is the best you can do in black. Using Necropotence and Chainer together requires a bit of math skills. There are times when low on life and cards that you can curse at it, but these are rare occasions.
Phyrexian Arena - One of best draw cards ever printed. Dropped on turn three, Phyrexian Arena will generally get us enough card advantage that we can keep a tight control on the board.
Entomb - In this deck, Entomb basically serves as a one mana instant speed tutor for your creature of choice. There are generally two ways to play this card. You can search for the answer of choice to help keep the field clear or search up a big creature to lay down the smack (usually Sheoldred, Whispering One).
Demonic Tutor - Pretty much the best tutor ever printed. I like to hold on to this card and search for whatever card I need to answer my opponent. I am also known to just search for Sheoldred and call it a day. This is probably my second favorite target for Xiahou Dun, the One-Eyed's ability.
Buried Alive - This card is especially strong in this deck. Often times when you pick the right cards, you can easly set yourself up for a win. It costs you three mana to dump three guys in the yard!!! This guy really helps shore up your board position and find those guys you need to stop your opponent's game plan. Generally speaking I will pick either or both of Sheoldred, Whispering One and Xiahou Dun, the One-Eyed along with whatever the board state requires.
Diabolic Tutor - Not the cheapest mana cost for a tutor, but it is a tutor that will find any answer you need. Equally important it does not allow your opponent to see the card and puts it in your hand for potential immediate use.
Liliana Vess - Liliana 1.0 generally serves as a one or sometimes two use Vampiric Tutor that may also act as a fog effect. Her ultimate is nice...but will never (or should never) happen. If you set her first tutor up correctly and then get the second one, you very well should will the game.
Harvester of Souls - Creatures die when playing this deck. When creatures die while this guy on the field, you start gaining card advantage. If you set things up correctly, you can easily draw two to three cards at a time with Harvester of Souls. In addition to his drawing prowess, Harvester of Souls also is a good sized body with deathtouch. He's great as a second or third target for Buried Alive
Bloodgift Demon - Bloodgift Demon essentially serves as Phyrexian Arena number two on a nice 5/4 flying body. While being a creature makes it more fragile than Phyrexian Arena, it can be reanimated and being able to swing in the air makes up for it most of the time.
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Sacrifice Outlets
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Sac Outlets are vital to reuse the ETB effects this deck thrives on, and more importantly to protect your guys from exile from Chainer's third ability.
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Altar of Dementia - Absoluely great sac outlet. Comes down cheap at two mana and lets you sac for free. On sacing a creature, lets you mill yourself or your opponent, possibly putting some juicy toys for Chainer in the graveyard in the process. Using it on yourself or an opponent is a judgement call.
Spawning Pit - This is probably my favorite sac outlet. It is cheap at two mana and lets you sac for free at instant speed. When you sac creatures, you get the ability to make tokens. I have been able to make a small army of tokens from this card before. The nice thing is, the effect is so subtle, that most players won't bother to kill it until its too late.
Attrition - One black mana to sac a creature and destroy a non-black creature. This is a situationally great sac outlet. Against most decks, this ability can be debilitating on top of the rest of the ways the deck has to kill creatures. I've completely locked an Azusa player down with Attrition before. However, against other black decks, this card is not so great.
Infernal Tribute - Infernal Tribute is the most expensive sac outlet in the deck, but also expensive to use at a two mana activation cost. Infernal Tribute lets you sac any permant so you can kill a Bitterblossom or Phyrexian Arena before they kill you in addition to being able to sac creatures.
High Market - Its a land that lets you sacrifice a creature for free (well you lose the one mana it produces) and gain life. As an easy to use land sac outlet, its amazing.
Miren, the Moaning Well - Its a land that lets you sac your creatures to gain life equal to their toughness. Its expensive to use at effectively 4 mana, but as a land its easy to get down and fairly hard to kill. The land can also gain you a decent amount of life over the course of the game if you have spare mana laying around.
Phyrexian Tower - Its a land that lets you sac your creatures to gain two black mana. This deck can be very tight on mana at times, and two mana when sacing something can open all kinds if possibilities.
Phyrexian Altar - Its probably the best sac outlet available since it makes B and can power out more Chainer activations.
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Lands
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This deck has several utility lands that fulfil particular roles and are very important to the inner workings of the deck.
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Cabal Coffers - Arguably the best mono black card ever printed. Some people say its the real commander of any mono black deck. Coffers generates insane mana with not too many swamps out on the field. With Deserted Temple and Rings of Brightheart an infinite amount. You really have to be careful when you play it, because Coffers does not like to stay on the field for long periods of time.
Urborg, Tomb of Yawgmoth - What's the absolute best way to abuse Cabal Coffers? By using this guy to turns all lands into swamps. All your utility lands, and Cabal Coffers itself now add to the total that
Cabal Coffers taps for. Just by itself, it makes it easier to get the black mana to abuse Chainer. Do be aware that Urborg does effect the opponent as well. I have inadvertently helped my opponents by dropping Urborg before.
Deserted Temple - How do you make Cabal Coffers better? you make it so that you can use it again for even more mana! Temple has a few more uses than even making infinite mana with Coffers and Rings of Brighthearth. You can get value by untapping Volrath's Stronghold, High Market.
Petrified Field - Cabal Coffers will die. Early and often. Petrified Field is nice enough to return Cabal Coffers to the field. Its somewhat redundant with Crucible of Worlds, but we will not always have access to Crucible when we want/need Coffers
Vesuva - This guys is whatever land you need at the time. At worst, its a Snow-Covered Swamp in a pinch, but this guy can copy any land of yours or your opponents. Its best for copying Cabal Coffers, but it is also useful for killing Gaea's Cradle or Academy Ruins if needed.
Bojuka Bog - It may seem counterintuitive, but sometime exiling a graveyard can save you from nasty spelling getting reused against you. If your opponent has a Time Warp sitting in the graveyard and you know they have ways to return it, its best to nuke it while you have the chance, even if you lose a few good creatures.
Volrath's Stronghold - We send a lot of our creatures to the yard with high frequency. If we need, this guy can return a creature to the top of the Library so we can play it next turn. This is fun for chaining Fleshbag Marauder if chainer is not available. Another good use of this is returning Sheoldred, Whispering One in the late game so you can hard cast it and not worry about getting exiled.
Verdant Catacombs/Marsh Flats - These are 2 of the 4 fetchlands available to the black mage. These guys serve the purpose of smoothing out our land drops and thinning the deck. With Crucible of Worlds, having any one of these guys out will give continuous land drops even if we have no lands in the hand.
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Utility
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Every good deck needs lots of utility to function in all situations and this is no different. It has mana ramp, various extra removal, and additional ways to reanimate when Chainer isn't online.
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Yawgmoth's Will - Everything in the graveyard gets an extra crack at wreaking havoc. An absolute winner and black staple.
Sol Ring - On of the strongest cards in Commander for a reason. It can allow some stupid plays such as turn two Braids.
Crucible of Worlds - This guy is here to abuse the fetchlands. With Crucibler and a single fetch we have a guranteed land drop every turn, if at the cost of 1 life. The card also has a few more subtle uses. When out, he helps mitigate the effects of running Smokestack or Strands of Night, both or which can put a bite on our mana base.
Mimic Vat - Creatures will die when this deck is live. Mimic Vat gives you another way to bring guys back and with haste no less. With a nice ETB guy attached, this card gets even more value.
Rings of Brighthearth - One of the most criminally underrated cards in the deck. It allows you to so many extra things. Activate Chainer twice but only play two for the second activation and more importantly no life...yes please. Activate Cabal Coffers twice, again yes please. Kill two critters with Liliana of the Veil or exile two with Karn Liberated. SOLD
Gauntlet of Power - Gauntlet is a strong mana ramp card and buff for black land and creatures, but its not without some drawbacks. It only works with basic land and also works for your opponent. Giving my opponent's creatures +1/+1 and his swamps two mana generation can hurt, but generally Chainer is better designed to take benefit from the effect.
Caged Sun - This deck can get mana hungry as you try to grind out a win. Caged Sun doubles your black manaand gives a +1/+1 boost to your creatures. At six mana, its not the cheapest mana artifact, but it is definitely the best since it does not effect your opponents.
Oblivion Stone - There are times when you need the field dead. Creatures we usually have have no issues with, but we occasionally get overrun by a token deck if we can't get Massacre Wurm online. Artifacts and enchantments prove to be the bane of this deck more often than not and OStone does a great job taking care of them for us. Oblivion Stone is the reset button for bad situations.
Reanimate - One black mana to bring back any creature in any graveyard. Its especially fun early if you also have an Entomb handy. The life cost is prohibitive, but the answers it can bring are generally worth it. Depending on the need it can be used as a kill spell to return Fleshbag Marauder or bring back one of your power 6 such as Sheoldred, Whispering One or Braids, Cabal Minion.
Exsanguinate - This card can bring you back from the brink of defeat or win you the game in one swoop depending on how much mana you have available. I probably when the highest percentage of games on the back of Exsanguinate and a mana doubler such as Nirkana Revenant.
Living Death - The card has several uses. It is a wrath, but not in the traditional sense. Since we pack Blood Artist, Falkenrath Noble and Massacre Wurm, we can make this card do a lot of heavy lifting for us and Xiahou Dun, the One-Eyed can bring it back for shenanigans so we can repeat over and over.
Beacon of Unrest - There are very few ways for black to return artifacts from the graveyard. This card is nice enough to give reusable artifact or creature recursion from not only your graveyard, but from your opponents as well. Five mana is a beat steep for a reanimation spell, but it is one of the most versatile in the game.
Damnation - The cheapest Wrath effect that black has access to. I'm not generally a fan of wrath effects of a spell in this deck, but if you have one, this is the one to have.
Karn Liberated - Karn Liberated is an expensive answer card at seven mana. However, he is the answer to literally everything. When he hits the field whatever card is giving you the most issues: Gone permanently. Generally its best to hold him till you need him, but you can also put him out and do his +4 ability either as a distraction or to attempt to get his ultimate. His ultimate is rare, but it most definitely wins games.
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General Strategy
With Chainer, the deck obviously revolves around the graveyard. The collective graveyards in the game essentially serve as a de facto second hand for you to play from. To feed Chainer's ability you need creatures in the graveyard: your graveyard and your opponents' graveyard. For your own graveyard, Entomb &Buried Alive allow you to get creatures you like in the yard so you can reanimate them at will. Your opponent's creatures are a bit more tricky. There are a few ways to abuse your opponent's graveyard. The best way is to play the deck is to give yourself the option to kill whatever hits the field. Kagemaro, First to Suffer, Fleshbag Marauder, and Bone Shredder give you reusable, self sacrificing, ETB creatures to put your opponent's toys in the graveyard for Chainer to play with and keep you from dying at the same time. To further help control the field, Braids, Cabal Minion & Smokestack like to stay around and blow several things up each turn, especially in tandem. You can also force your opponent to discard creatures. Mindslicer nicely empties hands, removing any counterspells or kill spells in addition to the possibility of pitching cuddly creatures for us to play with. Occasionally the best approach is to just mill your opponent. With large mana out, Geth, Lord of the Vault can throw huge numbers of cards in an opponents yard to play with.
After playing Chainer, you realize two things are very important to augment his ability. First, you need life gain to offset paying three life for each activation or you will burn through your own life total quickly. Many games I find that I do more damage to myself than my opponents do in the early game. To offset the life payment, Blood Artist and Sangromancer go a long way toward keeping the life total up. Yes, they require creatures to die, but the way this deck functions that should never be an issue. Second, you need sac outlets to make sure your creatures do not get exiled when Chainer dies. The best sac outlets are free to use, cards like Spawning Pit and Altar of Dementia make great value adding outlets for creatures you do not want exiled or creatures with nice ETB's you would like to use again.
To win with Chainer you have a few options. First, can just beat the opponent down with your guys, or better yet, you roast them with their own guys. Now, this deck is not an aggro deck nor was it ever designed to be. You will win some games by turning guys sideways, but this deck mainly serves as a nickle dimer deck that takes a few hits here and a few hits there and grinds out a win once the opponent starts running out of blockers. Luckily we have other options to kill the opponent, or at least finish them off. The deck can very easily burn the opponent for a win. Falkenrath Noble can slowly (or not so slowly) ping an opponent to death just by sitting on the field while the deck does what it does. Kokusho, the Evening Star can form a death loop with Chainer given a sac outlet and enough mana or at worse burn your opponents a few times and gain a ton of life in the process. The most used and most reliable win condition for this deck is probably Exsanguinate. With Xiahou Dun, the One-Eyed, if the first, or second, or third Exsanguinate doesn't get past counterspells, we have an engine to retrieve it for use later.
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Notable Synergies
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There are a good number of strong cards in the deck, but there are certain lines of play between two or three cards that can set you ahead.
One of the reasons people use Chainer over other mono black commanders is for the infamous death loop with Kokusho, the Evening Star. With a reusable sac outlet (a free one is preferable) you can play Kokusho for three black mana and three life with Chainer's ability, sac Kokusho, and then repeat the process. For a mere twenty-four black mana, Chainer and Kokusho can deal a full forty damage to the field while Exsanguinate would only deal twenty-two Damage with this mana. This is probably the strongest kill condition out of nowhere for the deck, but it takes three pieces to set up and can be easily disrupted. I've found its best to leave searching for Kokusho for later in the game. Early in the game you like more field control cards and having Kokusho in the graveyard prematurely can be a liability.
Chainer and Fleshbag Marauder/Slum Reaper are essentially best friends. They are his best options for nuking the field in a hurry. Since the ability allows them to sac themselves, they nicely return themselves to the graveyard to be used again. The big issue with this form of control, is you will burn life fast controlling the field this way. Enter Sangromancer. Sangromancer turns locks with Fleshbag Marauder into instances that gain loads of life instead of putting you in a huge hole. Since she gains three life, in a one on one game she nullifies the life loss and in large multiplayer games, she can potentially gain as much life as Kokusho or more.
Braids, Cabal Minion is absolutely one of my favorite cards to play, with her artifact comrade Smokestack not far behind. However, she can horribly backfire against you if you do not plan out her usage. Braids' absolute favorite play toy is Bitterblossom. With Bitterblossom out, Braids will have zero effect on you while your opponents lose their creatures, lands, and artifacts. The ability to eat artifacts and lands, especially early, makes Braids a powerful tool. There are also other tricks to not losing advantage to braids. With Sheoldred, Whispering One or Chainer out, you can sac braids to herself, or better yet, sac her to something like Spawning Pit at the end of your opponent's turn and then replay her for your opponent's turns. If reanimation is not online, Reassembling Skeleton gives a two mana reusable creature to sac every turn.
While on the subject of Reassembling Skeleton, there are some hilarious plays that he can be a part of. The most obvious use the skeleton is along with Skullclamp as a reusable three mana way to draw two cards. His utility does not stop here though. He is totally abusable with all of the sac outlets. If you are sitting around with mana and have no other use: blow up the skeleton, bring him back, rinse and repeat. With Spawning Pit, I've seen Reassembling Skeleton fuel twenty-five tokens while playing with his good buddy Pawn of Ulamog to curb his mana consumption. With the Altar of Dementia it is possible to mill out an opponent late in the game; again, Pawn of Ulamog helps effectively double the number of cards he can mill.
So Xiahou Dun, the One-Eyed is good, but how exactly do we use him for the most effect? Chainer can return creatures, so we generally want to get back strong sorceries or enchantments. Xiahou Dun is as good as whatever he can return, so want want to return the strongest cards we can. Targets 1 and 1A are Exsanguinate and Demonic Tutor. Exsanguinate is a game winner; if it gets countered or you needed it to gain life to survive...get it back to use again. One game I had Xiahou Dun fetch Exsanguinate three times. The first two uses were countered, the third kept me alive and the fourth killed the table. Fetching Demonic Tutor really opens the game up for you on options and lets you fetch exactly what you need. I do occasionally find more strategic uses for Xiahou Dun, the One-Eyed. I like returning Sheoldred to my hand with Xiahou Dun. Returning creatures with Chainer is always a liability, so when I have an opportunity to play a creature not attached to him, especially the power creatures, I take that opportunity. Sheoldred generally returns the favor and starts a loop of returning Xiahou Dun each turn and then grabbing whatever other black card I need. Another fun loop, and possible win condition, with Xiahou Dun is with Living Death. Living death lets you return all the creatures in your yard, including Xiahou Dun, to the battlefield. You can then sac Xiahou Dun to return Living Death and repeat the process as long as you have the mana to do so. If you can manage to get any of Blood Artist, Falkenrath Noble, or Massacre Wurm on the field or in the graveyard as you start your loop you can either win outright, or deal a significant chunk of damage to the field.
Rings of Brighthearth is one of those cards that has so many potential abuses that they just must be chronicled. EVERY activated Ability gets a replay for two mana. With a card such as Expedition Map or a fetch land such as Marsh Flats, the ability is cute, but not necessarily game breaking. However, most of the other cards you can use rings with can get bonkers. The two absolute strongest uses of rings, and even more so at the same time, is with Deserted Temple and Geth, Lord of the Vault. Using rings on Deserted Temple allows all kinds of bonkers plays. When Deserted Temple untaps Cabal Coffers it generates infinite mana, so long as you have enough swamps, that can be used to fuel a Kokusho Death loop, an Exsanguinate, or a huge pluck and mill fest by Geth, Lord of the Vault. Geth so nicely plays with rings due to his X ability. If there are two eligible cards with the same converted mana cost in a graveyard, you can use rings to copy the ability with the X you payed. It doesn't take too many activations with rings and Geth to generate huge advantage and possibly mill an opponent out of the game. There are other cards that like to get on the rings party as well. Chainer is quite fond of rings as he can reanimate a second creature without paying life. . All the planeswalkers are especially fond of rings as well. Rings also turns Bloodline Keeper from a small-time token producer to an army in a can and potential win condition.\
Credit of course to "jmdt" for the original primer on mtgsalvation.