Meren of Clan Nel Toth, The Devil of EDH (EDH / Commander)

Opponents Sacrifice: 6

Fleshbag Marauder
Merciless Executioner
Plaguecrafter
Archfiend of Depravity
Grave Pact
Sheoldred, Whispering One

Token Generators: 3

Izoni, Thousand-Eyed
Grave Titan
Avenger of Zendikar

Drain Cards: 6

Gray Merchant of Asphodel
Kokusho, the Evening Star
Blood Artist
Zulaport Cutthroat
Syr Konrad, the Grim
Torment of Hailfire

Ramp: 10

Sol Ring
Rampant Growth
Cultivate
Kodama's Reach
Birds of Paradise
Sakura-Tribe Elder
Farhaven Elf
Viridian Emissary
Search for Tomorrow
Black Market

Card Draw: 10

Skullclamp
Grim Haruspex
Disciple of Bolas
Deathreap Ritual
Evolutionary Leap
Moldervine Reclamation
Smothering Abomination
Wall of Blossoms
Phyrexian Arena
Read the Bones

Targeted Removal: 7

Reclamation Sage
Caustic Caterpillar
Viridian Zealot
Hero's Downfall
Tragic Slip
Acidic Slime
Ravenous Chupacabra

Protection: 7

Dark Privilege
Pattern of Rebirth
Swiftfoot Boots
Lightning Greaves
Yavimaya Hollow
Heroic Intervention
Spore Frog

Boardwipes: 3

Massacre Wurm
Damnation
Toxic Deluge

Tutors: 6

Birthing Pod
Pattern of Rebirth
Demonic Tutor
Diabolic Intent
Buried Alive
Fauna Shaman

Recursion: 7

Victimize
Yavimaya Hollow
Apprentice Necromancer
Eternal Witness
Mikaeus, the Unhallowed
Meren of Clan Nel Toth
Sheoldred, Whispering One

Repeatable Sac Outlets: 8

Ashnod's Altar
Birthing Pod
Evolutionary Leap
Carrion Feeder
High Market
Phyrexian Tower
Altar of Dementia
Viscera Seer

How to win with this deck:

NO INFINITE COMBOS IN THIS DECK THAT I AM AWARE OF, DECK WAS NOT BUILT TO GO INFINITE :)

This deck can win 1 of 3 ways

1: Drain opponents by bouncing/recurring/triggering the drain cards listed above. Syr Konrad, the Grim and Blood Artist can easily be triggered over and over by sacing off tokens and forcing opponents to sac their stuff and take damage for it. While not identical these cards ( Zulaport Cutthroat and Vindictive Vampire ) are similar, but only benefit from you sacing off creatures, but the concept still applies. Protect yourself and sac off what you can to drain your opponents and heal yourself.

You can bounce/recur both Gray Merchant of Asphodel and Kokusho, the Evening Star to drain your oppoennts for massive damage multiple times per turn using Mikaeus, the Unhallowed, Meren of Clan Nel Toth, and even Victimize and Apprentice Necromancer can be used to recur it to close out a game if you need to trigger it just 1 last time to win etc.

2: Ashnod's Altar + Token/Creature sacing or Black Market + Torment of Hailfire can easily close a game providing it doesn't get countered.

3: Combat damage is another easy way to win with this deck using the massive token generation this deck can pump out by bouncing/recurring Izoni, Thousand-Eyed, Grave Titan, or Avenger of Zendikar. The key pieces for this are Mikaeus, the Unhallowed, Meren of Clan Nel Toth, Panharmonicon, and Strionic Resonator. While it might be niche it could come in handy to know that you could also use Apprentice Necromancer to help bounce/abuse Grave Titan specifically.

Apprentice Necromancer can be sac'ed to fetch Grave Titan from the graveyard. It gives haste, so you'll get the ETB for the Tokens, you can swing for 2 more tokens, you can then proceed to bounce/recur this card with the right set up another 3 times totaling without Panharmonicon or Strionic Resonator 5 triggers and 10 2/2 Tokens in 1 turn. You could technically get 12, but what's the point of Sac-ing off Apprentice Necromancer again when you won't get it back via Mikaeus, the Unhallowed for the 2nd time?