Oblivion Ring effects are almost always powerful. When a new one is printed, the question to ask is how best to utilize it and what advantages does each available Oblivion Ring variant have over the others. In Standard, we have quite a few exile effects – we have Baffling End for small creatures, Conclave Tribunal for decks with early board presence, Seal Away for slower decks to fight against aggressive or evasive threats, and Teferi as a late-game answer to permanents that also threatens to take over the game via card draw. Deputy of Detention isn't strictly better or strictly worse than any of these options, so today we will closely examine when and how best to utilize this new way to exile all the things. We will also discuss its Modern applications.
I shot the sheriff
But I didn't shoot the deputy
This is what we are hoping for with Deputy of Detention, that no one ever kills it to get their exiled permanent back. Much like most of the other Oblivion Ring-type permanents, the card exiled by it returns if it leaves the battlefield. This makes the creature variants a bit more fragile than their enchantment counterparts. For instance, Detention Sphere and Deputy of Detention are very similar except that killing a three-toughness creature is generally easier than killing an enchantment. So the Detention Sphere is a more reliable answer to an opposing permanent. The flipside is that you can usually do more things with creatures. For instance, you can flash a creature onto the battlefield at instant speed with Aether Vial, you can blink creatures much more easily than you can enchantments, and creatures can attack and block and crew vehicles. In the case of Deputy of Detention, you can also protect it from a potential kill spell with Brave the Elements, which is not something you can say for Detention Sphere.
Another important difference between Detention Sphere and Deputy of Detention is that the deputy has the "until" wording instead of two separate abilities. This means that unlike with Fiend Hunter, you can't stack the triggers to permanently exile the first target. For example, If I cast Fiend Hunter or Detention Sphere or Oblivion Ring, and then with the targeting ability on the stack I flash Flickerwisp onto the battlefield via Aether Vial, I can essentially exile two permanents instead of one, the first of which will be gone permanently while the second target will be the one underneath our card. No such shenanigans can be played with Deputy of Detention, unfortunately, but this has becomes the standard way to word these type of effects in recent years. So this should come as no surprise. I just wanted to point out that it works this way instead of the older more powerful way.
Also unlike Detention Sphere, you cannot target your own permanents. Detention Sphere had a "may" clause, which made it such that it would never backfire like Oblivion Ring sometimes would. So being able to target your own permanents was a bonus. Deputy of Detention is worded like Banishing Light in that you can only target opposing permanents. This is really only a minor drawback since the vast majority of the time you'll want to target an opposing permanent anyway, but it does remove some of the flexibility.
To make up for this lack of flexibility of removing the "may" clause and the ability to target your own permanents, they also removed the "not named [this card]" clause, which means you can in fact exile an opposing Deputy of Detention. This is a worthwhile tradeoff because it means you can not only exile an opposing Deputy of Detention, but if they have multiples you get to exile all of them to get all your stuff back! Since it only exiles opposing permanents, it will only exile all opposing copies of Deputy of Detention, leaving your copies still on the battlefield continuing to exile all the opponent's stuff.
This also avoids the infinite loop where the game cannot proceed. It used to (and probably still does) crash Magic Online when Oblivion Rings were involved in such a loop. The loop is where I use Oblivion Ring to exile your Oblivion Ring, which causes an exiled Oblivion Ring to return to the battlefield, which exiles the Oblivion Ring I just played, which causes the Oblivion Ring under it to return, which then exiles the Oblivion Ring that was just returned, which causes the previous Oblivion Ring to return, which causes that Oblivion Ring to be exiled, which causes the other Oblivion Ring to be returned, ad infinitum. When the Oblivion Rings involved are the only permanents on the battlefield, the game could not proceed and it would start over or end in a stalemate. Deputy of Detention fortunately is worded in such a way where that would not be the case and the loop is avoided.
Given that a big appeal of control decks is rendering opposing removal spells useless, I don't think they will be in the market for Deputy of Detention. If it's one of few creatures in your deck, it will have a huge target on its back and the opponent will happily deploy one of the useless removal spells that have been rotting in their hand all game on it as soon as it is played. In post-board games I could see control decks potentially wanting to board these in because the creature heavy decks against which Deputy of Detention shines brightest typically only play a handful of removal spells and can therefore usually afford to sideboard out all their removal spells in favor of better anti-control cards. Against a post-board configuration of a heavy creature deck against a control deck (i.e. in the absence of removal), the Deputy could potentially be very strong. But control decks almost certainly would not want this card in their main deck.
Aggressive decks, on the other hand, are very much in the business of wanting this type of card. It is a threat that can be pumped up by anthem affects while also serving as a quite cost-efficient and versatile removal spell. People are comparing the card to Banisher Priest and Fiend Hunter, which in the majority of cases is an apt comparison (at least in Standard), but being able to target artifacts, enchantments and planeswalkers instead of just creatures is very relevant. Instead of your removal spells being virtual blanks against control decks, suddenly they become one of your best cards as they can help get rid of an opposing Teferi or an opposing Seal Away. Having your removal spells be good against control decks cannot be understated.
I could see white weenie splashing blue for this card along with maybe a few other cards. It matches up excellently against History of Benalia, which is one of the defining cards of Standard right now. If you exile the token, then even if they kill your Deputy they do not get their token back. And henceforth you have a three-toughness body to block the remaining two-power Knight Token (except for the one turn where it gets pumped by History to a 4/3). It is also just a straight-up decent blocker against a bunch of 2/1 creatures. It can also reset Ajani's Pridemate back to zero counters even if they kill the deputy.
Given that the deputy is so good against white aggro, I expect a lot of people will want to play it. And given that it's not great in control decks (at least main deck), I suspect the place people will try it is in their own white weenie decks, especially given how easy it is to splash blue in Standard off four Hallowed Fountains and four Glacial Fortresses. The three spot on the curve is admittedly pretty tight, but I think there is room for deputy. Here is a place I would start:
I think there is also space for Deputy of Detention in Modern. This is where not being able to blink it to get double triggers really hurts it the most, but the tradeoff is that the versatility of exiling a permanent instead of just a creature is amplified. Given the diversity of Modern compared with Standard, there isn't just one deck that blanks your removal spells. Instead there are several. And also unlike Standard, there are numerous noncreature permanents that must be dealt with. For instance, games involving Ensnaring Bridge often hinge entirely on whether the creature deck can get rid of the bridge. Deputy of Detention will shine brightly in such games. Similarly, being able to exile a Cranial Plating or Worship or Daybreak Coronet is miles more useful than simply being able to exile an opposing creature.
There are two decks that I think would make best use of Deputy of Detention in Modern. The first is Bant Company and the second is Death and Taxes.
This is the list Steve Locke played to a Top 4 finish at an RPTQ except I replaced Reflector Mage with Deputy of Detention. In a deck like this that capitalizes on tempo, the versatility provided by Deputy compared to Reflector Mage is huge. It gives us an answer to opposing problematic permanents and we can find it off Collected Company, which means we can fairly reliably find it each game. Between Spell Queller and Deputy of Detention, this deck packs quite the ability to interact with whatever the opponent is doing, and can do so on the opponent's turn.
This is where I would start with Death and Taxes:
Deputy of Detention is a great way to crew Smuggler's Copter and is a nice tandem with Spell Queller. Between Deputy of Detention, Flickerwisp and Spell Queller, this deck has quite a few ways to stop a problematic card from taking over the game or to disrupt a combo. I'm not sure which of these two lists is more promising, but each gains versatility from Deputy of Detention. Based on current trends, probably the Bant deck is better due to its overall power level and positioning in Modern right now, but that can change.
Deputy of Detention is a welcome addition to the pantheon of Oblivion Ring effects. It won't be an all-star in the main deck of control decks, but will be great in white weenie mirrors and potentially also as a sideboard card in control decks against aggro decks. I also expect it to provide additional versatility to some of the Aether Vial decks in Modern. Overall I think the card is poised to be a hit!
...Then again, I may have a slight bias toward white creatures with disruptive abilities.