If you managed to read everything here I just wanted to say good luck assembling your Lazav deck. You have made a great choice in commanders and I hope that your deck in whatever capacity brings you as much joy as mine has. Please feel free to ask me any questions if you have them and i'll be sure to answer as soon as I can. May you deceive your friends and dash their hopes and dreams with your superior mind!
Update 8/24/16: Just discovered EDHREC.COM found some interesting cards that I added to the maybe board going to try playtesting a few and see if I am going to include them. The ones that I am most interested in are Trepanation Blade and Life's Finale both seem to have some really good synergy with the deck so we'll see if they make the cut. Spinal Embrace & Grafdigger's Cage both were removed to make room. Grafdigger's Cage is fantastic but I have other cards that fill this role so it is a little redundant despite how powerful it is. Spinal Embrace falls victim to simply being too expensive even though it's very powerful.
This is probably my 50th change to the deck and if you have taken anything away from my story, Commander decks are always in a state of evolution and change.
Update 8/30/2016: Rotated out Perplex and Shadowmage Infiltrator for Dimir Charm and Notion Thief. Perplex can be too easily countered in my opinion to make it a viable counter spell while the transmute is a nice touch I already have plenty of tutors that do the same thing better. Dimir Charm can be used to mill it can counter sorcery's which isn't as broad as Perplex but their isn't an exception. Overall it provides I believe better utility in the areas I need. Shadowmage Infiltrator would be great if artifact and black creatures weren't so prevalent in the format. I simply am not getting the card draw from it and it ends up just turning into a chump blocker in my playgroup. Notion Thief is the logical replacement I have used this card before with some success however I never liked that in order for me to draw cards I had to wait to flash him into play at the exact moment your opponent plays a massive draw spell, otherwise they simply won't cast or use draw outlets and wait until he's been removed from play.
Update 9/1/16: Pulled one Swamp for a Sunken Ruins as well as an Island for Strip Mine. The Filter Lands are great for cards with tricky devotion like Lazav. As mentioned before in the description getting a few more noteworthy duels has been a priority and is very important in this deck.
Strip Mine is just amazing and is another utility element that this deck greatly needed. A means to deal with nasty lands that can ruin the game plan, for example Maze of Ith.
Update 12/14/16: Pulled Bloodchief Ascension for Chromatic Lantern. I know this may seem like a random change but while I really like the idea of an infinite combo being a possible win condition in the deck unfortunately this combo is just too hard to achieve with this deck. Obtaining the 3 quest counters needed in order for it to activate is at times surprisingly difficult most players can see the combo coming and respond accordingly. Duskmantle Guildmage is still in the deck and can trigger this effect just the same. Chromatic Lantern will help the deck cast more spells with Nightveil Specter, and it also helps with mana fixing and ramp.
Update 12/15/16: Pulled Szadek, Lord of Secrets for Sepulchral Primordial. Yes Szadek has a fun, and strong effect that does synergize well with the deck assuming Lazav is in play, however he does take a few swings/turns before his ability really starts to make any difference, not too mention you aren't getting any combat damage. I am sad to see him go, but my playgroup is experiencing a bit of a power creep as of late which means he simply doesn't make the grade anymore. Sepulchral Primordial costs around the same mana but it's enter the battlefield trigger is very powerful and effects the board immediately upon it coming into play. In addition to these changes mentioned I have been slowly filling out the deck in small doses. I will be finally adding in a Damnation but it has not arrived in the mail just yet. I can't wait!
Update 12/18/16: Pulled Ponder for Whispering Madness. This one still is going to need a little more play testing but I am pretty sure that the deck really doesn't need Ponder as much as it did before I added in Sensei's Divining Top. Also I made some changes in regards to the description for the card Soul Ransom.
Update 12/20/16: Damnation! I finally own a copy! Thrilled to finally have the card in the deck, pulled Mimic Vat in order to make room for it. Mimic Vat is a great card, but the exile sometimes can be counter intuitive. I am considering loosing Soul Ransom for Phyrexian Arena but I'm not positive what I want to swap in order to add the card into the deck. I do think a little extra card draw wouldn't be a bad thing to include in the deck I just don't know what to pull.
Update 2/24/17: After a few more games at the my local card shop, I am definitely going to be making a couple of changes. Soul Ransom is going to be pulled for Necropotence as soon as I obtain another copy of for it, and I am considering trying Crypt Incursion and/or Extract from Darkness. Crypt Incursion was a random card I came across while sifting through a friends deck and it seems like a very powerful effect giving the deck a little life-gain while also disrupting recursion strategies. As for Extract from Darkness, there is no denying it's a powerful effect, however I just don't know if there is anything I am willing to pull for it.
Update 2/27/17: Necropotence replaced Soul Ransom and I pulled Altar of Dementia for the always useful Talisman of Dominance. Altar has always been more of a backup plan for my deck and not really central to the deck's win conditions despite it being a great sack outlet. Talisman simply a great ramp card that helps speed things up. I may consider rotating the Altar back into the deck but more play-testing and time will only tell.
Update 3/09/17: Another noteworthy change is on the horizon after trading in a ton of bulk cards to Channel Fireball I have a good chuck of credit to really invest in the deck. Two Noteworthy cards that I will be rotating into the deck are Mana Drain and Underground Sea. In Addition I am considering pulling Fabricate for Trophy Mage, and finding homes for Thought Scour, Cryptic Command, Cemetery Puca and Avatar of Woe.
Update 3/11/17: Rise of the Dark Realms, Dimir Charm, Fabricate, and Hedron Crab have been rotated out for Thought Scour, Avatar of Woe, Counterspell, and Trophy Mage. Currently this is simply at a test level but the reasoning is sound, as of right now it seems like the best decisions to make.
Update 3/29/17: Mana Drain, Codex Shredder, and Disallow have replaced Shadow of Doubt, Trinket Mage, Sphinx's Tutelage. Currently my playgroup is experiencing a "powercreep." As a result more and more nasty things have found ways to easily stick to the board with the lack of counterspells that are currently being played. This last change has been to help the deck better answer some of those nasty threats. While I loved Shadow of Doublt it simply was too situational only being used to target tutor spells or the activiation of fetches which while awesome, simply isn't as verstile as a hard counter such as Mana Drain. Sphinx's Tutelage has never really proven itself to be too gamebreaking when it's in play at best getting maybe 4 to 6 cards from a single opponent when I draw, so instead I swapped it for another hard counter Disallow. Finally and a hard one to do Trinket Mage for Codex Shredder. While I love Trinket Mage greatly for it's ability to fetch a few of my one costed spells, Codex Shredder will better allow me to combat tutor effects and hit everyone with mill.
Update 4/4/17: Replaced Trepanation Blade for Snapcaster Mage. Pretty Strait forward exchange, the mage is amazing letting the deck reuse counter spells or other useful instant or sorcery cards in the graveyard. Trepanation Blade is a great card with a ton of synergy with Lazav, however it's triggered ability isn't consistent and as we know consistency is power.
Update 4/25/17: Replaced Dimir Guildgate & Dimir Aqueduct for Cavern of Souls & Vesuva. This change is pretty simple to understand, the cavern makes Lazav uncounterable, and vesuva just is a very in theme utilty land that offers the mana base a little flexibilty when needed.