NOTE: This list will be changing often as cards are considered, tested, and either slotted in or rejected for others. Please consider this a building block for your own ideas and please feel free to expand upon the concept.
So, Muldrotha - just about everybody has made some kind of brew with her, and the majority have settled for EDH value or cEDH Stax builds.
I think she can be better, and this is my attempt.
So, to begin with I want to talk a little about what I see the commander's role as for this deck. Instead of using her as a very clunky loop for infinite mana and re-use (very vulnerable to any sort of instant disruption,) I see her instead as a way to recover the board after an emergency nuke. That nuke being Mindslicer.
Hitting the board with the nuke empties the hands and quite possibly delays any combo decks from going off. We can't completely hold off a top-deck draw after nuking, but the odds that a single top-deck will enable a combo win are smaller than letting the combo-player have a full grip and getting that same top-deck. On the contrary, nuking our own hand will let us recover anything necessary from the graveyard through a variety of permanent recursion via Muldrotha; or through cards such as Jace, E-Wit, or Snapcaster. Vulnerability is still high to graveyard disruption, but that is the risk that we take and live with, and that risk would still remain regardless of the commander because of the specific strategy we are running: Reanimator.
The specific reanimator combo we are aiming for is Walking Ballista/Mikaeus/Free Sac outlet through various runs of Razaketh tutor lines. Complementing this is a package of threats that work to either disrupt OP hands or strategies. The deck is not fast-combo, aiming to usually win on turn 3-5 (the average being turn 4) but has potentials to hit the table with soft(ish) locks that significantly advance our own advantages while destroying card advantage from the OPs.
The first of these is the Mindslicer nuke discussed above. It won't stop a top-deck, but it empties the hands and allows us a breathing space to recover. You need to be sure about your set-up to continue moving forward from this point, but there is a significant amount of ramp to allow this.
The second soft lock is through a rapid reanimation of Jin-Gitaxis. The benefit here is through the seven-card draw at the end of turn that refills our ammunition, potentially discards more important fatties that we want to reanimate on the next turn, and either forcing the discard from our opponents or forcing them to answer the threat and spend their mana to do so. A failure of the table to present an answer locks them down into top-decking, but also continually re-applies the lock and keeps them in the top-deck while we cycle through the deck as rapidly as possible to find the finishers.
Razaketh needs no real discussion as to presence, save that you most certainly want to have a minimum of two other creatures on the board (preferably mana dorks) before he lands in order to fetch.
Protean Hulk is the general first fetch target once Razaketh is on-line, and the reanimation target of choice once you are ready to end the game. Two notable lines to consider off of the trigger: First, pop the Hulk to fetch Viscera Seer, Mana Dork of choice (usually BOP if he isn't out already), and Mindslicer. Sac the Slicer to Raz (or the Seer if we're on a Flash/Hulk) to empty OP hands and force their responses immediately. With Seer on the board we can save our creatures if necessary and set up for a later Muldrotha turn, with Raz on the board we can set up for later reanimation lines. The Seer is also useful to protect Raz from an exile spell. From this point we can continue to go off without concern for OP interference and win on the spot. Another possibility would be to put in Teferi, Archmage of Zhalfir and use that as a substitute for the Mindslicer/Dork portion of the Hulk fetch, but that particular Teferi does not advance our position outside of our own turns, costs a lot, has no relevant ETB/LTB triggers, and doesn't affect our OPs in the same manner that Mindslicer does; for me at least. Your mileage may vary.
The second line of the Hulk is to just immediately get Mikaeus/Ballista. We're using Ballista here instead of Triskelion precisely for the reason that it can enter with Mikaeus off of a Hulk sac, and with any sort of free sac effect can be used to end the game. Ballista also offers all of the other early-game advantage presented by an interactive piece on the board. If M/B come on to the board without the assistance of a free sac outlet (but through the Hulk/Razaketh line) Razaketh can use the Ballista to get an outlet and keep it on the board with the Undying triggers.
Other notable cards:
Siren Stormtamer - Can be used as a protection spell against targeted effects. Specifically against your graveyard. A good counter to keep up when you're going off but haven't locked out OP hands through Mindslicer, or when you're pulling up your first big reanimation target from the grave.
Magus of the Abyss - this one is useful after a Slicer Nuke; drop in Muldrotha, drop in Magus, keep saccing it and returning it to the board while developing. Useful in forcing off OP mana dorks and creature threats. Possible cut for better threats, should be considered a free slot if something more appealing or threatening would slot in better.
Cryptbreaker - good for dumping your reanimation targets and putting out that necessary second creature for Razaketh to exploit. If in a stall can be used after two discards to become a Phyrexian Arena on demand, which can also be used to go off quickly through a top-deck tutor spell like Wordly Tutor, Mystical tutor, Vampiric Tutor.
Bloom Tender - With a large mix of creatures in various colors this becomes decent, though not always perfect. Notably, this one is in the deck but not Priest of Titiana. Testing has showed that PoT and Tender do both have bad boards, but Tender can make multi-colored mana whereas PoT cannot, so she won out.
Exploration - Opening hand Exploration with multiple lands is amazing, and can advance the clock significantly. If the game drags out the enchantment is still useful through Muldrotha as it will allow a top-deck land drop and then a graveyard land drop, thinning the deck. However, this is a meta-call on my part, as the cEDH scene in my LGS notably does not include a large number of Blue players. If sideboarding is allowed by the table I would immediately switch this enchantment out for Carpet of Flowers, as it is simply superior. However, against Food Chain Prossh and Sevala Brostorm (the two most common OP players in my LGS) Carpet of Flowers is simply dead at every point of the game. Again, YMMV.
Ipnu Rivulet - This underrated land has decent potential for both offense and enabling our own combo. Re-playable with Muldrotha in the late game if you are looking for reanimator targets from the stall. Offensively you can use it in response to top-decking tutors to mill out whatever they went looking for.
Hermit Druid - Because of how our end-game Raz/Hulk lines work this card isn't in there to dump the entire library into the graveyard and try to go from there. Instead, his presence is there to dump a section of our library into the graveyard in an attempt to dump out a reanimation target. It's a more dangerous line to follow because Muldrotha in and of herself will alert everyone to have their graveyard hate up and ready if possible, but it can either land the combo or help in the post-nuke game in trying to find the finish.
Notable Absences:
Underground Sea and Imperial Seal. Don't have either, cost is out of reach at the moment. Would definitely add if possible.
Gaea's Cradle - Not a good card for this deck. Despite all the creatures in the deck, there will rarely be a time where you have more than two or three on the board when you are going off. Yes, that's three mana from Cradle...but it isn't black, and black mana is what we generally need to close the game. If the game goes long Cradle will make a lot more mana...but Muldrotha being out will often mean that we are only operating out of the graveyard, not from our hands, and if we needed the extra mana to hard-cast something from the grave, we're horribly off script with our plan. YMMV. Also, doesn't help that this is another card I don't own, but the deck functions solidly enough without it.
Dark Ritual - Simply put, any sort of instant speed mana ritual is useless for us in the combo, as we can easily tutor up LED/Phyrexian Altar/Lotus Petal to get the mana necessary to finish. In the early game it could be useful, but only if we have more black spells to drop than green/blue. Having it as a one-of in the deck is too random to guarantee usefulness as opposed to any other spell that would be removed for the slot.
Necromancy - Too expensive at 3cmc to function optimally during the combo. May re-evaluate after more practice with the deck. YMMV.
So, strengths of the deck: Very good disruption package that allows for a better recovery from the symmetrical wipe than OPs. Solid reanimator lines that both allow for that same disruption wipe and then a continuation of the reanimator strategy past any responses before the disruption takes effect. Good soft-locks with card advantage. Great tutors. Can fight through stax via the Commander.
Weaknesses of the deck: Graveyard hate. Heavy counterspell disruption. Slower than fast-combo decks. Bad runs of mana-dorks/lands.
The last one is difficult to compensate for, as we need a solid package of dorks to power out the reanimation package, hold up answers, and present fodder for Razaketh to enable us to go off. However, there is a sigificant number of times that the deck will present nothing but a long run of dorks/lands and no way forward. Advice and thoughts about how to minimize this would be appreciated.
There it is, advice and criticism appreciated.
