Metallic Mimic will ensure that Marchesa always enters with a counter. Just name humans or wizards as you creature type, she ETBs with the counter. Nigh immortal Marchesa.

This deck is a nightmare to play against! A fun nightmare but still a nightmare!

Nice start. I do have a few suggestions to help you lower your avg. cmc though and I'll try to break it down by category and suggest a cut.

Draw: Midnight Reaper , Yawgmoth, Thran Physician , and Skullclamp for Butcher of Malakir (Grave Pact if your mana can handle it but Butcher is overcosted and susceptible to more removal), Bedevil (versatile but single use and not abuseable here), and Necropolis Regent (Really good at what it does but there's better finishers for Marchesa).

Control: Glen Elendra Archmage (combos with Mikaeus and Goblin Bombardment also) for Mystic Confluence (Glen Elendra gets multiple uses, Confluence only 1).

Boardwipes: Last One Standing and Jokulhaups for Decree of Pain (You won't need extra cards with Jokulhaups and it's cheaper to cast) and Polymorphists Gest (Last One Standing is the same cost but effects all opponents rather than 1).

Win Cons: Gray Merchant of Asphodel and Kokusho, the Evening Star (both very abuseable with Metallic Mimic to ignore the Throne and win outside of combat).

Discard: Sadistic Hypnotist and Oona's Blackguard (discard helps seal up games tighter than a dolphin's butthole) for Vilis (Marchesa does better with cheap aggro) and Underworld Connections (You'll have better results out of resource denial than a single use per turn draw).

Expensive Suggestions: Sneak Attack , Diabolic Intent , Imperial Recruiter , Grave Pact , Necropotence , and Spellskite

Feel free to check out my list for inspiration, it's one of the top rated Marchesa lists on this site. Upvotes on any of my decks are appreciated. Every Masochist Needs a Marchesa To Love Them

Last_Laugh thank you for your suggestions and for advertising your deck and asking for upvotes.

First off, Butcher of Malakir is staying in the deck because it is a reusable grave pact effect. If it gets removed I have ways to get him either by Marchesa or other effects. Bedevil is a cool card with amazing art by Seb McKinnon so that's not leaving either. Necropolis Regent helps with getting +1 counters and is a super cool looking vampire. Mystic Confluence is a versatile counter spell so if I don't need to counter something I can do other things. Decree of Pain is great because of the card draw and the versatility with the cycling effect. I'm going to be losing life anyway so Villis will give me card draw and the activated ability might actually be able to get rid of a creature (rare I will admit but possible). Underworld connections, not gonna lie just really like that card. As for Polymorphist's Jest, I put that card in all of my decks with blue. It's surprisingly powerful, no one really expects it and the flavour of it is absolutely hilarious! It's my pet card and I will 100% not ever take it out of this or any other deck!

As for your suggestions, I appreciate it, I have yet to test the deck as it is (I recently upgraded it) but I may add Sneak Attack and Midnight Reaper, those are fun suggestions. I don't want to be playing Gary nor Kokusho in this deck because that's not how I want the deck to win, If I do find that my deck lacks finishers, I'll consider adding them in as well but as I said I need to do some play testing. Glen Elendra, Sadistic Hypnotist and Oona's Blackguard I am definitely not putting in because I hate resource denial. I want to play Magic WITH people not have people watch me play because they have no resources. To me the fun part of Magic is the interaction that you get with the other players. Which by the way, adding Glen Elendra countering almost every spell my opponents cast I do not consider as interaction! So adding this cards in, literally make it less fun for me. In the same vein Jokulhaups... really? Talk about resource denial and no fun. I do not do any land destruction. I also will not use Diabolic Intent because I generally do not use tutors unless it directly helps the strategy (Like in my Elsha spellslingers deck I have enlightened tutor and mystical tutor because they're instants so it advances my game plan and I'm manipulating the top of my deck which I want to be doing. Go check out my deck if you like and give it an upvote it's the number one Elsha deck in my play group).

Also the peek of my mana curve is at 3, my avg. cmc is at 3.4 and I have a good amount of ramp that I have never been stuck with a card in hand that I can't cast after turn 6 or 7.

All jokes and pissy-ness aside, thank you for your attempted help and thank you for putting so much detail and effort into your suggestions. But I'm not looking for any suggestions, I did a while back, and after going through those I'm happy with where the deck lies. And also a lot of the cards that you suggested I remove were some of the first cards I put in the deck and some of my favourite cards (Polymorphist's Jest is honestly one of my favourite cards in all of Magic, if not my favourite). I have the deck here not for suggestions, but because I'm proud of it and I want to show it off. It's a ton of fun to pilot and it's a huge threat at the table. Although this isn't an optimized Marchesa deck and it's not one of the top Marchesa decks on this website, it's a damn strong one and a fun one, and more importantly it's my Marchesa deck.

Also very ballsey of you to ask for upvotes without even upvoting any of my decks ;)

Pissiness is right... welcome to ignore you ungrateful little piece of shit!

'Also very ballsey of you to ask for upvotes without even upvoting any of my decks' Are you fucking kidding me? I took the time to type that whole fucking thing out to help you and THIS IS YOUR SHITTY UNGRATEFUL ATTITUDE?!? I upvote decks when they're deserving... not this piece of shit list.

• Oof, Last_Laugh really is just out here on some elitist baby bullshit huh? That's a bad look, my dude.
• Anyways, the deck looks great. A friend of mine played a similar deck and it was always a blast to go against. Strong and tricky, but fun.

Hordebane thank you on both accounts! I was worried about the first point, and I'm happy that you like my deck! :) It is such a fun deck to pilot!

Spark Double can be INSANE in this deck. Copy Marchesa for double dethrone triggers. You can always change what Spark Double becomes on re-entry too.