COMPETITIVE UPDATE: (See Update for details)

REMOVED

• Acidic Slime

• Awakening Zone

• Butcher of Malakir

• Demon of Dark Schemes

• Diabolic Servitude

• From Beyond

• Gray Merchant of Asphodel

• Green Sun's Zenith

• Grim Backwoods

• Mazirek, Kraul Death Priest

• Necromantic Selection

• Reclamation Sage.

• Scavenging Ooze

• Sepulchral Primordial

• Solemn Simulacrum

• Smothering Abomination

• Swamp x 1

ADDED

• Beast Within

• City of Brass

• Contamination

• Demonic Tutor

• Elves of Deep Shadow

• Fyndhorn Elves

• Golgari Signet

• Gravecrawler

• Greater Good

• Krosan Grip

• Mana Confluence

• Massacre Wurm

• Nim Deathmantle

• Phyrexian Altar

• Protean Hulk

• Smokestack

• Vampiric Tutor

Hey there. Your deck looks interesting. I played a Meren deck myself for a very long time. I have some questions and general suggestions based on my experiencie playing in my local EDH league, which is quite competitive. Hope they help :) :

-Why did you include Protean Hulk, listed as a finisher, but haven't added the rest of the combo (Phyrexian Delver, Walking Ballista)? By itself, Hulk isn't such a great card.

-If you intend to make this deck more competitive and consistent, I'd highly recommend cutting cards that don't impact the board the turn they come in. I'm thinking Grave Pact and Dictate of Erebos. Smokestack can be too slow as well. In my experiencie these cards can be somewhat winmore; you already have lots of removal so most of the time you don't really need to add more sacrifice effects. Speaking of removal, you have to add Shriekmaw and Ravenous Chupacabra, they are bombs in a Meren deck.

-If you can, make room for Elvish Mystic. It helps with Contamination, and mana accelerations is just allways good to have. Adding Dryad Arbor and Green Sun's Zenith wouldn't hurt either.

-I'd cut back on the amount of highly costed bombs (5 or more CMC), and focus more on efficient creatures with enter the battlefield or sac effects that you can abuse. Reclamation Sage, Manglehorn, Skinrender come to mind. Also, Caustic Caterpillar.

-Add some more card draw/card advantage if possible. Meren can be really strong but is easily disrupted; you need more engine cards to keep the deck going if Meren is killed too many times. They are expensive, but if possible try and add Sylvan Library, Survival of the Fittest and Oracle of Mul Daya. Tireless Tracker, Nissa, Vastwood Seer  ^Flip, Courser of Kruphix and Smuggler's Copter are other really powerful and cheap cards that generate lots of advantage.

-Having some wraths effects in the deck can be useful too. You can rebuild from a boarwipe much faster than your opponents; exploit that. Toxic Deluge and Damnation are the best.

-Other useful tutors to consider, and which help increase the deck's consistency are Diabolic Intent and Eldritch Evolution, which synergize with your game plan. They can help you find the right card for each situation.

-Mindslicer can win you the game all on it's own.

-Finally, Sadistic Hypnotist is awesome.

Meren is great (she was my first commander and really got me hooked with the format), so I wish you have great success with her!

mvas Thank you for your feedback and suggestions. I appreciate your thoughts.

I have Protean Hulk listed as a win condition because he is powerful in bringing out the ETB effects I need when I wanted them, even without the combo. I try to limit my combos because I prefer a much more reaction-based play style; rather than combo searching style.

Grave Pact and Dictate of Erebos allow me to control the board on my opponents turns. Similarly, Smokestack passively burns away at my opponents board; more progressively the longer it remains on the board.

Elvish Mystic, I missed that in my add of mana dorks. Thank you!

I removed Green Sun's Zenith in favor of Vampiric Tutor.

I appreciate where you are coming from with the ETB effects. But in my LGS Meta there are an ABUNDANCE of Humility-style control players. So investing in the ETB this heavily is quite the gamble for me.

Many of the cards you list in the draw/card advantage paragraph are definitely in my Acquireboard... but my budget hasn't allowed me to get them just yet. In time, I will get them. Damnation and Toxic Deluge are also coming soon.

Diabolic Intent and Eldritch Evolution were omitted in favor of Demonic Tutor and Birthing Pod respectively.

I'm just waiting for Mindslicer to be in stock at my LGS and then it's going in.

Took a look at your updates. The deck seems way sharper than before.

Cards I would consider cutting: Kokusho, the Evening Star -- Kokopuffs is awesome, but his usefulness varies from deck to deck. If his lifegain has been needed to keep you alive, or you have killed people by repeatedly saccing him, keep him. If not, I'd consider cutting him.

Sheoldred, the Whispering One -- very powerful, but in my meta she tends to get killed quickly. If you have trouble getting her out/getting her back I'd consider cutting her.

Yahenni, Undying Partisan -- A 0 cost sac outlet. I understand the need, but I think you could do better.

Vraska's Contempt and Vraska, Relic Seeker. I mention these only because, not having played with or against them I am unsure of their strength. If you feel the need, use them.

Cards I would consider adding: Considering I don't play Meren, and your deck seems way better than before, take these suggestions with a grain of salt.

Sac outlets: Altar of Dementia -- cheaper than Yahenni, and if you're into self-mill, well...

Perilous Forays -- way more expensive to cast, and saccing costs, but it has an obvious upside.

Protection: Don't know if this is an issue for Meren, but Lightning Greaves is cheap, and Asceticism, while expensive, protects all your guys.

Other: Regrowth is a great all-around recursion card, possibly useful, and Buried Ruin can recur artifacts if you're worrying about that.

I have tried to suggest cards I haven't seen mentioned before. Other cards suggested by other should maybe come first (Sylvan Library should be at the top of the list of cards you add, I think). For the Rivals of Ixalan cards, the tutor seems a bit weak, but the others may be worth looking into.

markbeloit Thanks as always for your feedback. Sorry I haven't gotten back sooner. Life is getting in the way of MTG lately.

I think your feedback regard Kokusho, the Evening Star and Sheoldred, the Whispering One are spot on. However, I very consistently kill or lockout the whole pod with these two. Kokusho keeps me in the game, and Sheoldred fuels my sac outlets and secures my board position. That said, I usually only play Sheoldred when I have enough counters on Meren to bring her back at the end of my turns.

Yahenni, Undying Partisan has been clutch many times over. Surviving board wipes and getting bigger and better throughout the game eventually lets me steamroll opponents.

Vraska's Contempt is nice spot removal against planeswalkers. In my meta, there are a fair amount of superfriends. Otherwise, I would take it out.

Vraska, Relic Seeker is great in this deck. She gives me a 2/2 pirate to sac if necessary; or gives me great removal coverage (and 1 mana) to boot. Her ult is great, but I've never had to use it.

Altar of Dementia: I am limited my self-mill to what is already in the deck. The local LGS Meta has been splashing in Graveyard hate recently, so I don't want to fall victim to the well times Graveyard cleanse.

Perilous Forays: Seems like a great sac outlet. I will do some play testing to see if she brings value to the deck. If the deck went wide, I think it would be very worth it; but I don't often go wide until late game at which point, ramping may not be relevant.

Protection isn't really an issue because I sacrifice so much of my own guys to get Experience Counters.

Regrowth and Buried Ruin are great recursion cards; but I try to limit the recursion in this deck to be from Graveyard to Battlefield for maximum efficency.

Sylvan Library: This is at the very top of my list. This deck really needs a draw engine. Greater Good is an awesome draw engine but to be able to bolster it with Sylvan Library would be amazing.

After testing, I find that Rivals of Ixalan doesn't offer that much to the deck. The most notable addition would be Journey to Eternity  ^Flip but it is very situational.