How about Increasing Confusion? Especially during the mid/late game phases, this can really start to hurt. Keening Stone could also really increase the speed of your opponents' downfall. I see you're using Whispering Madness; you could also add Paranoid Delusions. Maybe not as powerful, but still ... Last but not least, equipping Mirko with the Sword of Body and Mind would make him even scarier.

Hey, awesome deck! You might want to consider adding Shizo, Death's Storehouse to your manabase as another way to make Mirko unblockable.

Brave running mill in a primarily multiplayer format. Upvoted.

@HauntinYou - Thanks for the great comment!

1. Withered Wretch seems like a great idea and I'll have to find a place for it.

2. Fatespinner is another great card I'd love to add for pillow fort reasons.

3. It is a very nice combo but it would require taking away too much of the deck so I probably won't include it. I also like to have cards in graveyards for other cards in the deck.

4. Wrexial, the Risen Deep is a really good card, but it doesn't actually contribute to milling so I'm on the fence about adding it.

5. Nemesis of Reason is a card I've always wanted to add but just never really found a spot for so I'll have to see.

6. Riddlekeeper is another definite card I want to add!

7. I had Szadek, Lord of Secrets in the deck at one point and I even tried using him as the commander, but he never was able to do enough by the time I finally cast him. Maybe things have changed and I'll have to try him again.

8. I like the idea of Shred Memory but the combo is just in there because the cards are good on their own and I think I'll stick to the Withered Wretch for targeted graveyard removal.

Thanks again for the extensive comment!

@NV_1980 - Increasing Confusion was in the deck at one point as well as Paranoid Delusions but neither did as much work as I thought they would and they both only target a single player which does not work great in a 6-player game. As for Keening Stone, it is already in the deck and Sword of Body and Mind is definitely a card I want! Thanks!

@scaredcrow4 - Adding Shizo, Death's Storehouse sounds like a great idea!

@jon_hill987 - Thanks for the positive comment and upvote!

@metalheadforlife25 & Fujjji - Thanks for the upvote!

Thanks everyone for everything!

Suggestions:

Cyclonic Rift -- ??? Put this in.

Ill-Gotten Gains -- ayy lmao that's a fun one

Warped Devotion -- yis. put this in. yis.

Body Double -- ayyyyyy

Checkout Fleet Swallower and Fraying Sanity

Psychic Corrosion could be pretty good.

Maybe try crawl space instead of the silent arbiter its a little harder to remove or even run both.

esperslap not a bad idea thanks!

Trepanation Blade gives any creature Grind for one when it attacks, while also dealing more combat damage potentially.

Keening Stone and Nemesis of Reason? Would maybe drop Jace Beleren for one of them as it's unlikely you'll hit the -10 in a game.

I like unconventional decks so +1 on this, love to see an EDH mill deck.

My Zur deck (Don't worry... I've got an enchantment for that) ended up turning into a sudo-mill deck with Zur being used to lock down my opponents while I mill them, so you might find a few more useful cards in that.

Headers13

I did actually at one point have Keening Stone in the deck, but the reason it and Nemesis of Reason are not in the deck is because they do not fare well in a multiplayer setting and can end up being too resource heavy (although they can be quite fun).

On the other hand, that's why I quite like Jace Beleren as he is card advantage mainly for me with the upside of incidental draw/deck depletion for my opponents.