This is a pretty straight forward deck that wants to use Persistent Petitioners' mill ability (which is free, mana wise) in conjunction with your commander (which is mana intensive) in order to very quickly kill one opponent at a time. This is more easily accomplished if you activate Duskmantle Guildmage twice so that your opponent loses 2 life for each card milled. If you hit all your land drops and have sufficient petitioners in hand, you will be set up to mill 12 and deal 12 damage on turn 5 and double up on turn 6. That means you can't win until turn 8 unless another player also did some serious work on peoples' life totals.
The deck structure is based around not having any draw power in the command zone. We have several powerful draw sources in the deck, but for the sake of consistency, we are not counting on having them every game. That's why there are enough petitioners in deck to make sure you have 4 or more by turn 5 (12 cards seen) most games. The rest of the deck is a few utility cards and tutors to make sure we can get the utility cards we need.
Trinket Mage and Dizzy Spell can go get Slagwurm Armor for defense in games that you can't close out quickly, Relic of Progenitus to get rid of graveyards for decks that know how to weaponize them. Trinket can also be used to grab a land of any color with Seat of the Synod and Vault of Whispers. Drift of Phantasms is solely to search for Rhystic Study, but could be used for defense in a pinch. The rest of the utility cards are all for bouncing creatures. Bouncing an enemy creature at a key time can buy you just enough time to kill, and bouncing your own creature lets you get around this deck's second biggest weakness, which is an Arrest-like aura on your commander, which stops you from turning mill into lost life. Every tutor in the deck except for Drift of Phantasms can tutor for a bounce effect.
The biggest weakness of this deck is board wipes like Pestilence and Crypt Rats. We simply don't have the draw power to recover from losing our petitioners. Counterspells seem like the only reliable way to defeat these, but this deck needs to be using all its mana proactively, or its lack of defenses will get it killed before you can kill your opponents. If a boardwipe gets onto the stack, your only hope is to have held your mill and mana for the Guildmage so you can kill the person in response and remove their boardwipe from the stack. I haven't had it happen yet, but it seems like this deck has a lot of potential for ending up in stalemates where you can't kill somebody because they will respond by crippling you, and they can't make a move against you without you responding by killing them. It would feel very similar to how many games with Aetherflux Reservoir end.
