Well what do you know--Leovold is still legal in this format.
The reference in the name to the Dark Clerks is taken from Terry Pratchett's Discworld novels and is the group upon whom the deck is modeled after. In the books the Clerks are portrayed as a shadowy group of multi-class account/bureaucrat/assassin/spies who can kill people either with knives and poison, or paperwork and red-tape. Yes, we're talking Advisor Tribal! Exciting, no?
Well, it will be exciting for us.
This deck revolves around the dozen Persistent Petitioners (read: Dark Clerks) in Leovold's employ. The petitioners' second ability allows you to tap four of them (and their boss too--Leovold is an advisor) at instant speed, milling your opponent for 12 cards. You can do this at instant speed, without bothering about things like summoning sickness, because the ability is expressed as a "cost" rather than a ability. In effect the ability is tapping the four advisors rather than the other way around. Bureaucracy, I tell you.
Twelve cards out of a 50 card deck is pretty damn huge. Even better, our Dark Clerks have ways of untapping thanks to cards like Dramatic Reversal and Vitalize. Our bomb untapper though is Quest for Renewal. Activate the petitioners' ability once with this card out, and you will be able to untap them on every player's turn thereafter. In a four player game, you might easily be milling 48 cards(!!!) on one rotation of play around the table.
Taking advantage of all these tapped advisors, we're playing Harvest Season which allows us to thin our deck and put a ton of tapped basic lands into play (usually 4) for some staggering ramp. We have other ways to ramp too with Cultivate, Sapphire Medallion which lessen our costs and Propaganda which makes it harder for others to attack us while we are laying our plans.
Our leader, Leovold, Emissary of Trest, brings everything together for us. His ability to limit card draw keeps our opponents from accessing the resources they need to win, and when combined with our scry, and card draw cards (Path of Ancestry (choose "Advisor"), Arcane Denial, Confound (which both double as counterspells), Night's Whisper, Pilfered Plans, Serum Visions) gives us card advantage as long as our devious leader is in play.
Beyond that, Leovold makes difficult for others to remove our Petitioners thanks to his second ability which allows us to draw cards anytime someone targets one of our permanents. Given that there are a dozen petitioners in the deck, losing one while Leovold is out might result in drawing another to replace them (especially if we have thinned our deck a bit with Harvest Season already).
Not every creature in the deck is an advisor. We also have a pair of spirits: the unblockable Dimir Infiltrator, and the flying "wall" Drift of Phantasms. They are both in the deck for a couple of reasons. First the Infiltrator (a 1/3) is unblockable, but can itself provide some early blocking. Likewise, our Drift can can fly and is a 0/5. More importantly they have transmute and combined allow us to tutor for all but 2 of the remaining non-land cards in our deck. Incidentally, Muddle the Mixture--a slightly limited counterspell--also has transmute. These tutors allow us to pick the cards we need when we need them. Need to ramp with Harvest Season or require a fourth Petitioner? Need to guarantee a Dramatic Reversal, or a Quest for Renewal? Just transmute them up.
We also have a dangerous wizard on staff--the Duskmantle Guildmage. With this wizard and a little mana we can turn all those cards that our subversive bureaucrats are milling into direct player damage, and even force a little bit more mill when needed.
Finally, in addition to milling everyone at the table out of the game, our Petitioners, Drift of Phantasms, and Infiltrator can all benefit from Assault Formation. With the Formation in play, the Drift can be turned into an effective 5/5 flyer that can attack, while the Infiltrator and Petitioners all become 3/3s (or better if you can pump them with Formation) and the Infiltrator can not be blocked. Such is the danger in confronting Leovold's Dark Clerks.
There are some other cards you could put into the deck if you want to get Leovold banned in Tiny Leaders as well as Commander--cards like Ashiok, Dream Render, Laboratory Maniac or Sphinx's Tutelage, but even I am not that mean.
This is a relatively expensive deck. The dozen Petioners we need for this deck themselves currently run a dollar a piece. The three most expensive cards in the deck (aside from Leovold himself--who at the time of this post clocks in at about $8) come in at total of about $40. Those cards are Chromatic Lantern ($8), Propaganda ($10), Sapphire Medallion ($18-21, my copy is an older one and therefore more expensive). Basically, these cards provide in order: mana fixing, defense against faster creature decks, and ramp. While ramp, and fixing can be mitigated in part with some cheaper options (like some Guild cluestones or signets or other artifacts like Kefnet's Monument), Propaganda is tough to do without if only for thematic reasons. One can easily imagine the Dark Clerks conducting a Russian hack ("Leovold cares about working-class families who are top decking", etc...) to influence the outcome of the game. Some possibilities might include adding in some more ramp/fixing, something from the Maybe List to make the deck run faster or smoother, or perhaps an additional counterspell.
Sadly, there is no replacing the totally evil Leovold as commander, because at present no other legal Sultai leaders exist to take his place. According to the Official Tiny Leader's Blogsite the Sultai proxy "Sultai", a 2/2 Legendary Creature (with no creature subtype) for , was removed from the proxy commander list by the advent of Leovold himself (all according to Leovold's devious plan). That said, you can do what you like within the confines of your own play group, and having the option of playing the free proxy over the more expensive Leovold, seems reasonable. You might even be able to talk your group into allowing "Sultai" the 'Advisor' creature subtype for the first game at least. ;)
