Going to build this :D

Noctem: I am glad to hear it. Please keep me posted on how it works for you and what you would change after playing with it.

Sounds good, I'm starting to assemble the missing pieces. Will give feedback :)

Deck seems pretty good. I would definitely add the High Tide package back, don't worry about Capsize, but High Tide, Bubbling Muck (especially with Urborg), Frantic Search, Candelabra, and Time Spiral are all worth running.

Other things I'd consider adding are Cabal Ritual to Ad Naus, Necro, or Doomsday easier, and Sensei's Divining Top for the obvious card selection ability but also because once on board it can open Doomsday piles for free. Also maybe consider Riftsweeper in case of Lab Man getting exiled. Doomsday Zur runs Pull from Eternity for the same reason, Lab Man is the only real win condition.

Cuts I'd suggest are Tezzeret (hurts too much off Ad Naus), mana dorks (don't really fit the plan of going off after an EoT Ad Naus), Jeweled Amulet (slow, does nothing the turn you play it), Personal Tutor (slow and not able to get anything like Seal), Day's Undoing (awful for comboing), Winter Orb unless it really really hurts the rest of your meta.

To make up for the lost ramp from dorks, you can add Carpet of Flowers (assuming there's other blue players around), Talisman of Dominance, Fellwar Stone, potentially the Signets, or at least Dimir Signet, Mana Vault, maybe Gilded Lotus, and Voltaic Key.

I know a lot of those suggestions are for Storm decks, and this deck doesn't technically win with Storm, but you're doing a very similar thing. Make lots of mana, cast wheels or Ad Nauseam to make more mana to win off Doomsday. The Storm engine is very very good at doing that even if you don't finish with Tendrils.

Hope this helped a bit, glad to see more people with actual competitive decks :)

atr0s: Thank you for your insightful and thoughtful post.

I have noticed there are three major schools of thought for Leo among the cEDH scene:

1) Mana dorks, wheels, and DD win condition (what this deck is all about). In my opinion this is the fastest and most consistent way to lock down the table through disruption. DD is just an easy turn 4-6 win after the soft lock is in place and resources are skewed tremendously in my favor.

2) Mana dorks, wheels, and Hermit Druid win condition. Very close but the need for no basics tends to make the deck more green/black. There are advantages and disadvantages to this strategy, but is probably close in power level. ShaperSavant has a good brew for this style of deck.

3) Mucktide Storm brew: AKA what I think you are suggesting. Is represented by the work of Manbearscientist on reddit. I have limited experience with this style of Leo but it seems quite strong. I suspect it is slower getting to the primary combo (Leo plus wheel/Puzzle box), but it is a bit more resilent overall and has a good alternative win condition in tendrils.

A strong case could be made for all of these strategies. As for your suggestions for this deck:

High Tide: Great card, but I don't want to invest the card slots required to support it.

Carpet of Flowers: Is an autoinclude for blue heavy metas. Will add it to the sideboard.

2cc mana rocks: Far too slow for my purposes. Even if I went all stormy these would not be included. I would rather do what sonnet666 has done with his excellent brew and use extra land per turn cards like Burgeoning and Exploration.

Bubbling Muck: Very dependent on urborg and I don't love crop rotation for this build.

Sensei's Divining Top: An excellent card that will most likely replace Jeweled Amulet.

Cabal Ritual: Ive considered it but I would rarely get threshold given my reset buttons. In this deck it is just a bad Dark Ritual.

Riftsweeper: I hate such cards on general principle. If someone is dumb enough to exile laboratory maniac, they will suffer a deamaningly long and unpleasant beatdown by 1 drop mana dorks or at least they will have me nipping at their heels the whole game. Even if they get rid of my win condition I can still lock them out of having a hand and reset all libraries with Timetwister to prolong the agony. One such display and I suspect they will steer clear of that foolish course of action ever again. Politics can be fun :-)

As for your suggested cuts:

Day's Undoing: Second best wheel in the deck. Absolute autoinclude. I don't care if my turn is over if I have put every opponents at 1 card to my 7, shuffled every graveyard and prevented future draws with Leo on turn 3. I Leo turn 2, wheel turn 3 with counterspell backup, cast and win with DD turn 4-5. There is no need to speed up the last step as the primary combo all but seals the deal most of the time.

Personal Tutor: It is limited but it gets wheels early enough for a turn 3 Leo+wheel.

Tezzeret the Seeker : Yes it hurts. It also soft locks the table out of thier hand for the rest of the game if it resolves.

Winters Orb: Perhaps a meta call but it hurts opponents much more than me since I run alot of mana dorks and mana rocks.

Jeweled Amulet: worst ramp I have. I'm testing it out since it facilitates a turn 3 Leo+wheel. Can be cut if needed.

I hope that adequately explains where I am coming from. I suspect that after some more thought and testing I will implement more of your ideas into practice. Thank you :-)

Thanks for the detailed post, I enjoyed reading it :)

Lilbrudder All reasonable points. I think if you don't want to run High Tide, going for Hermit Druid in addition to Doomsday is potentially a good idea. You can leave out Narcomeoba and Fatestitcher and just play Druid, Dread Return, and Deep Analysis. Gives you another way to cheaply enable a Lab Man win, and wins through Stranglehold or Aven Mindcensor, as well as being much less affected by taxes. The deck does lean a bit more BG if you do that, but a full suite of fetches, duals, and 5c lands will let you get enough U no problem.

And about Day's Undoing, I completely agree that it's good, I just wouldn't run it in the stormy build. For the more midrange versions like this (or mine), it's great.

Still not a huge fan of Personal Tutor but running it won't kill you. Could potentially just be Worldly Tutor if Hermit Druid was added. Otherwise leaving it alone is fine.

Winter Orb is good since dorks are staying (as they should in the non High Tide builds).

Definitely agree with switching Amulet to Top.

I really think Riftsweeper deserves a spot, you realistically won't kill a table with dork beats. Sure you can make someone's game miserable by locking them down after Lab Man is gone but that isn't going to stop people from going right for your Lab Man next game. It's the best way for some decks to make sure you can't win.

About Tezzeret, he's also fine to leave if Winter Orb is staying since it makes him less of a one trick pony and still useful if Box is in hand.

Overall I like the list, and might be taking parts of it for mine. Definitely adding Transmute Artifact if I can up the artifact count a bit. And probably Winter Orb too.

I've been following your changes to this deck for the past couple days and I just wanted to throw this idea out there: Thran Dynamo. It's a bit of a heavy cost in a mana rock, but it's perfect for working with Transmute Artifact if you want to trade it for Teferi's Puzzle Box.

Noctem: If you like longwinded explanations I am your man :-)

atr0s: I have actually been pretty tempted by Hermit Druid, especially with Memory's Journey and Deep Analysis to make a mini Doomsday pile with Gitaxian Probe, Dark Ritual, and Yawgmoth's Will. I also like what Worldly Tutor would add to the deck. It would require a pretty massive overhaul to implement, but it could definitely be worth it. Would you mind if I took a look at your list?

Roan: Thank you for your continued support :-) I feel like Thran Dynamo is a bit too slow for this deck and I don't have a lot of big spells to ramp into with it. Your suggestion did bring to mind a possible interaction between Mana Vault and Transmute Artifact though.

Turn 1: Mana vault

Turn 2: tap mana vault for 3 then transmute it for UU into puzzle box.

Turn 3: Leo

If I could find a consistent use for Mana Vault outside this interaction it might be viable in a more artifact-centric build (stax?). Being able to get puzzle box into play from my library for 1UU is pretty sexy.

On second thought I am probably going to make a hermit druid version as described soon

In that brew what do you all think of Liliana, Heretical Healer  ^Flip? She protects Hermit Druid in a fashion by flipping and reanimating him or by taxing the board a card each turn. She also provides free zombie. She seems like pure value engine in a slightly more creature heavy build. We could even go crazy and add Eldritch Evolution and Dark Confidant.

Between Leo, Spellskite, Force of Will, and lily the most fragile combo in the world is getting some resilience.

If you're going to play dedicated Hermit Druid I'd rather have stuff like Postmortem Lunge or Shallow Grave than Lili. She's a but slow.

I'll update my list then post it in a little while.

Very true. I was thinking of her in addition to lunge. While not as conpetitive I kind of want to make this mirroe version a more grindy midrange deck that can either win slow or fast. Maybe add more stax pieces

Mine is built kind of in that style, though at the moment I don't have stax pieces. Considering Winter Orb and Null Rod, and if I added those, maybe trying to find room for the Llanowar Elves trio. If you wanted to go really hard on the grindy stax plan, Chains of Mephistopheles, while it does stop you from increasing your hand size by drawing extra cards, is absolutely brutal for your opponents once they have no hand.

Here's my list http://tappedout.net/mtg-decks/leovold-midrange-doomsday/

Some stuff might look weird, I'm in the middle of cutting out a Yisan package that I started with in the deck. At the moment, it still contains a Green Sun's Zenith package and runs Eldritch Evolution. Trying to decide if I want to keep them or not, leaning towards yes for GSZ and not sure about Evolution, if you have any suggestions.

Ill definitely give you some feedback. Chains looks pretty nasty. I was also thinking Bitterblossom and The Abyss might do some work. I also like Phyrexian Revoker as a silver bullet, but perhaps that is a bit too hipster. If only braids was still around :-/

My issues with the Bitterblossom Abyss thing are that Bitterblossom is almost completely useless by itself, Abyss is pretty bad by itself since you want to keep your mana dorks and general on board, and many decks don't care about Abyss at all or can play around it fairly well.

On second thought I completely agree that The Abyss is pretty bad for competitive environments and it clashes with my deck. I was thinking Bitterblossom could help with Dread Return for Laboratory Maniac and I can also Eldritch Evolution the tokens into Hermit Druid. Not terrible but a bit too cute when a turn 1 dork can be evolved into labman on turn 2, followed by a Tainted Pact on my turn 3 upkeep to win the game during my draw phase To answer your question. Green Sun's Zenith is definitely worth a spot, but I would only use EE with pact.

Yea, I wouldn't bother with Bitterblossom when you have enough dorks (plus Hermit Druid himself) to sacrifice for Dread Return.

And I do play the Tainted Pact, so Evolution is probably ok.

Why chain of vapor?

It is just a really cheap removal spell that hits all nonland permanents. I can cast the turn I am about to go off to clear the board of an enchantment like Humility. It also can slow down generals like Zur the Enchanter and Yisan, the Wanderer Bard that can get around my card draw lock and reset a general like Animar, Soul of Elements. I suppose it can also protect my own permanents in a pinch. There is no other spell that can do these things so cheaply. This deck tends to have a small board state so getting it sent back at me is not too worrysome.

And if someone sacs a land to copy it and retaliate bouncing something of yours you draw with Leo. Bounce a nonland permanent, make them sac a land and eventually draw a card for U.

Exactly. Then I can wheel away the card I just bounced to make it go away for good.

Atros: After further consideration I will take your advice and drop Personal Tutor for Wheel and Deal. It is instant speed hand hate that fits my ideal turn 3 curve. It replaces itself and lets me keep my hand. Since I am usually only getting a wheel with the tutor why not cut out the middle man.

Seems like a good idea to me. Wheel and Deal has mostly earned it's spot in my list for being instant, which is even more relevant than normal for me since I run Merchant Scroll. It also has the benefit of being able to lock out people's hands after I've tutored or drawn combo pieces and want to go off and not discard them.

atr0s: Oh jeez I didnt even think about Merchant Scroll. That makes it even better

Could you explain how your Doomsday stack works? I'm mostly confused by Lion's Eye Diamond, as you can't go to cast a spell and then crack the Diamond for mana to use for the spell because of the whole "Activate this ability only any time you could cast an instant." bit.

Aside from that, glad to see Riftsweeper now make the list. It's such a good insurance to combo centric decks like this. Only thing I could think of to add is another Enchantment hate card. Perhaps Naturalize, Krosan Grip, or Reclamation Sage.

A Hermit Druid version sounds really interesting, and I would love to see your take on it. Praise the BUG gods and may they watch over this nasty bureaucrat.

@Catgroove: He uses Yawgmoth's Will. Play it first, then you can crack the diamond and play Lab Man and Gitaxian Probe from the grave to win.