Gotta be honest folks, this deck was a tough one. 

I had a difficult time figuring out how the archduke here was going to marry flavor and function while also showing off some Adventures in the Forgotten Realms (hereafter AFR) cards. Zariel generates devils, but there are exactly 0 other Devils in the set. (There are some Tieflings, which kind of count according to my research, but only one of those creatures is Mono-Red and it's pretty underwhelming.) Plus, I gave the Devil theme to one of the Tibalts already. Dragons aren't something I can do either, since multiple Sarkhans have staked a claim there. 

Barbarians were on the menu, because I was interested in the Barbarian Class (the only Mono-Red payoff for Die Rolling in the set, which I did want to include), but there aren't many Barbarians in the set, and the payoffs for the tribe in general aren't plentiful. I thought about finally doing a Goblin deck, but since Daretti is out there somewhere and he's actually a Goblin planeswalker, I wanted to wait to really heavily lean into the theme. That said, there are numerous Goblin cards in AFR, so I felt like I should at least touch on the theme here. 

...Like I said, a tough one. In the end, I went with a marriage of the main things that Red seems to want to do in AFR: make treasure, attack with a swarm of Goblins, play a couple Dragons, roll some dice, and cast a Magic Missile

Here's how it looks:

Magic: The Gathering TCG Deck - Zariel, Archduke of Avernus by Andy Hurst

'Zariel, Archduke of Avernus' - constructed deck list and prices for the Magic: The Gathering Trading Card Game from TCGplayer Infinite!

Created By: Andy Hurst

Event:

Rank: 0-0

Freeform (Casual)

Market Price: $10.31

Cards

Tavern Scoundrel

Color Identity:R

Market Price: $0.02

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/240341_200w.jpg

Whenever you win a coin flip, create two Treasure tokens. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")
{1}, {T}, Sacrifice another permanent: Flip a coin.

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Goblin Morningstar

Color Identity:R

Market Price: $0.05

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/243251_200w.jpg

Equipped creature gets +1/+0 and has trample.
Equip {1}{R}
When Goblin Morningstar enters the battlefield, roll a d20.
1—9 | Create a 1/1 red Goblin creature token.
10—20 | Create a 1/1 red Goblin creature token, then attach Goblin Morningstar to it.

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Unexpected Windfall

Color Identity:R

Market Price: $0.30

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/243382_200w.jpg

As an additional cost to cast this spell, discard a card.
Draw two cards and create two Treasure tokens. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

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Teetering Peaks

Color Identity:R

Market Price: $0.11

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/33448_200w.jpg

Teetering Peaks enters the battlefield tapped.
When Teetering Peaks enters the battlefield, target creature gets +2/+0 until end of turn.
{T}: Add {R}.

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Strike It Rich

Color Identity:R

Market Price: $0.22

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/240149_200w.jpg

Create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

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Critical Hit

Color Identity:R

Market Price: $0.02

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/243246_200w.jpg

Target creature gains double strike until end of turn.
When you roll a natural 20, return Critical Hit from your graveyard to your hand. (A natural 20 is a roll that displays 20 on the die.)

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Hoarding Ogre

Color Identity:R

Market Price: $0.08

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/243264_200w.jpg

Whenever Hoarding Ogre attacks, roll a d20.
1—9 | Create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
10—19 | Create two Treasure tokens.
20 | Create three Treasure tokens.

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Chaos Channeler

Color Identity:R

Market Price: $0.03

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/243304_200w.jpg

Wild Magic Surge — Whenever Chaos Channeler attacks, roll a d20.
1—9 | Exile the top card of your library. You may play it this turn.
10—19 | Exile the top two cards of your library. You may play them this turn.
20 | Exile the top three cards of your library. You may play them this turn.

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Smoldering Crater

Color Identity:R

Market Price: $0.10

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/212469_200w.jpg

Smoldering Crater enters the battlefield tapped.
{T}: Add {R}.
Cycling {2} ({2}, Discard this card: Draw a card.)

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Downhill Charge

Color Identity:R

Market Price: $0.25

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/58075_200w.jpg

You may sacrifice a Mountain rather than pay this spell's mana cost.
Target creature gets +X/+0 until end of turn, where X is the number of Mountains you control.

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Wily Goblin

Color Identity:R

Market Price: $0.26

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/144980_200w.jpg

When Wily Goblin enters the battlefield, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

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Earth-Cult Elemental

Color Identity:R

Market Price: $0.02

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/243305_200w.jpg

Siege Monster — When Earth-Cult Elemental enters the battlefield, roll a d20.
1—9 | Each player sacrifices a permanent.
10—19 | Each opponent sacrifices a permanent.
20 | Each opponent sacrifices two permanents.

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Farideh's Fireball

Color Identity:R

Market Price: $0.01

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/243306_200w.jpg

Farideh's Fireball deals 5 damage to target creature or planeswalker. Roll a d20.
1—9 | Farideh's Fireball deals 2 damage to each player.
10—20 | Farideh's Fireball deals 2 damage to each opponent.

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Goblin Burrows

Color Identity:R

Market Price: $0.33

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/93639_200w.jpg

{T}: Add {C}.
{1}{R}, {T}: Target Goblin creature gets +2/+0 until end of turn.

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You See a Pair of Goblins

Color Identity:R

Market Price: $0.10

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/243091_200w.jpg

Choose one —
• Charge Them — Creatures you control get +2/+0 until end of turn.
• Befriend Them — Create two 1/1 red Goblin creature tokens.

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Meteor Swarm

Color Identity:R

Market Price: $0.17

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/243157_200w.jpg

Meteor Swarm deals 8 damage divided as you choose among X target creatures and/or planeswalkers.

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Predator Dragon

Color Identity:R

Market Price: $0.71

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/27758_200w.jpg

Flying, haste
Devour 2 (As this enters the battlefield, you may sacrifice any number of creatures. This creature enters the battlefield with twice that many +1/+1 counters on it.)

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Mountain

Color Identity:R

Market Price: $0.04

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/215722_200w.jpg

({T}: Add {R}.)

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Subira, Tulzidi Caravanner

Color Identity:R

Market Price: $0.23

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/215664_200w.jpg

Haste
{1}: Another target creature with power 2 or less can't be blocked this turn.
{1}{R}, {T}, Discard your hand: Until end of turn, whenever a creature you control with power 2 or less deals combat damage to a player, draw a card.

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Fissure Wizard

Color Identity:R

Market Price: $0.01

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/221956_200w.jpg

When Fissure Wizard enters the battlefield, you may discard a card. If you do, draw a card.

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Plundering Barbarian

Color Identity:R

Market Price: $0.06

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/243047_200w.jpg

When Plundering Barbarian enters the battlefield, choose one —
• Smash the Chest — Destroy target artifact.
• Pry It Open — Create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

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Red Dragon

Color Identity:R

Market Price: $0.10

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/243285_200w.jpg

Flying
Fire Breath — When Red Dragon enters the battlefield, it deals 4 damage to each opponent.

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Battle Cry Goblin

Color Identity:R

Market Price: $0.43

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/243156_200w.jpg

{1}{R}: Goblins you control get +1/+0 and gain haste until end of turn.
Pack tactics — Whenever Battle Cry Goblin attacks, if you attacked with creatures with total power 6 or greater this combat, create a 1/1 red Goblin creature token that's tapped and attacking.

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Hulking Bugbear

Color Identity:R

Market Price: $0.04

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/243284_200w.jpg

Haste

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Browbeat

Color Identity:R

Market Price: $0.35

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/161766_200w.jpg

Any player may have Browbeat deal 5 damage to them. If no one does, target player draws three cards.

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Goblin Banneret

Color Identity:R

Market Price: $0.09

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/176437_200w.jpg

Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)
{1}{R}: Goblin Banneret gets +2/+0 until end of turn.

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Magic Missile

Color Identity:R

Market Price: $0.17

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/243430_200w.jpg

This spell can't be countered.
Magic Missile deals 3 damage divided as you choose among one, two, or three targets.

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Rust Monster

Color Identity:R

Market Price: $0.02

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/243401_200w.jpg

First strike
Sacrifice an artifact: Rust Monster gets +2/+0 until end of turn.

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Goblin Smuggler

Color Identity:R

Market Price: $0.01

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/192649_200w.jpg

Haste (This creature can attack and {T} as soon as it comes under your control.)
{T}: Another target creature with power 2 or less can't be blocked this turn.

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Zariel, Archduke of Avernus

Color Identity:R

Market Price: $3.38

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/243228_200w.jpg

+1: Creatures you control get +1/+0 and gain haste until end of turn.
0: Create a 1/1 red Devil creature token with "When this creature dies, it deals 1 damage to any target."
−6: You get an emblem with "At the end of the first combat phase on your turn, untap target creature you control. After this phase, there is an additional combat phase."

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Delina, Wild Mage

Color Identity:R

Market Price: $0.90

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/243256_200w.jpg

Whenever Delina, Wild Mage attacks, choose target creature you control, then roll a d20.
1—14 | Create a tapped and attacking token that's a copy of that creature, except it's not legendary and it has "Exile this creature at end of combat."
15—20 | Create one of those tokens. You may roll again.

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Swarming Goblins

Color Identity:R

Market Price: $0.02

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/243258_200w.jpg

When Swarming Goblins enters the battlefield, roll a d20.
1—9 | Create a 1/1 red Goblin creature token.
10—19 | Create two of those tokens.
20 | Create three of those tokens.

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Barbarian Class

Color Identity:R

Market Price: $0.11

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/243331_200w.jpg

(Gain the next level as a sorcery to add its ability.)
If you would roll one or more dice, instead roll that many dice plus one and ignore the lowest roll.
{1}{R}: Level 2
Whenever you roll one or more dice, target creature you control gets +2/+0 and gains menace until end of turn.
{2}{R}: Level 3
Creatures you control have haste.

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Dragon's Fire

Color Identity:R

Market Price: $0.19

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/243575_200w.jpg

As an additional cost to cast this spell, you may reveal a Dragon card from your hand or choose a Dragon you control.
Dragon's Fire deals 3 damage to target creature or planeswalker. If you revealed a Dragon card or chose a Dragon as you cast this spell, Dragon's Fire deals damage equal to the power of that card or creature instead.

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Goblin Arsonist

Color Identity:R

Market Price: $0.02

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/215574_200w.jpg

When Goblin Arsonist dies, you may have it deal 1 damage to any target.

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Dogpile

Color Identity:R

Market Price: $0.11

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/13260_200w.jpg

Dogpile deals damage to any target equal to the number of attacking creatures you control.

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Rapacious Dragon

Color Identity:R

Market Price: $0.14

ImageURL: https://tcgplayer-cdn.tcgplayer.com/product/219578_200w.jpg

Flying
When Rapacious Dragon enters the battlefield, create two Treasure tokens. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

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The Game Plan

Get out lots of Goblins and turn them sideways, while also winning some die rolls — seems easy enough! Our main creature base is made up of Goblins, with Hulking Bugbear the most impressive on pure rate and Battle-Cry Goblin with the highest ceiling. We don't care much about most of these, so we can send them into battle with reckless abandon, but there are nice payoffs with a few of our Rares. 

The dice rolls are important here too. Chaos Channeler is our best form of card advantage, and if it can go unmolested for a turn or two, we'll be in great shape. Hoarding Ogre goes super well with the Channeler, since the treasures make sure we're having a great time no matter what channel we're watching. Swarm of Goblins and Goblin Morningstar are both a little on the mundane side, but "winning" the rolls there are great boosts to our board state. 

Don't sleep on Goblin Smuggler. We have several pump effects and spells, pretty much all of which can be used after the crafty goblin enables an evasive hit. If it's a Goblin, the Burrows is a consistent boost on a little token. The trigger from Level 2 of Barbarian Class can work with the die rolls on the aforementioned Channeler or Ogre to make the unblockable creature bigger. And of course the Downhill Charge can be a wrecking ball. 

The removal here is pretty much par for the course with Red: we've got some solid direct damage, and that's about all we can expect. Dragon's Fire is a fine Incinerate variant, and it could conceivably do a lot more damage with Red Dragon or our souped up Predator Dragon on the board. Farideh's Fireball is a good catchall, while Magic Missile can be a big problem for our opponents on the right board. Plundering Barbarian will likely give us the treasure, but keep the Shatter effect in mind, too. 

The Rares

Normally I love the names they give legendary creatures, but Tulzidi Caravanner is a tough one. We don't have any context for Tulzidi, it's hard to spell, and Caravanner is kinda like putting in a USB drive, in that I never do it correctly on the first try. Name complexity aside, Subira is going to be pretty good for us. It's a super Goblin Smuggler, which we noted above is already an effect we're interested in. And if we empty our hand (not unlikely given the treasures we can conjure up), then her second ability can wind up giving us an additional...unexpected windfall. (I'll see myself out.)

Across Adventures in Forgotten Realms, there's no cooler payoff than with the die rolls than Delina. We aren't playing the Pixie Guides here to really go off, but 1 or 2 copies of Barbarian Class do an okay impression, and we've got plenty of high impact hits here — Red Dragon being the biggest whammy. Because they come into play and are attacking, each hit on the die roll is another 8 damage coming in! We won't need to win many rolls to seal that up. But even if we don't have the Dragon hitting in, we've got several ETB abilities it wouldn't hurt to trigger, like Wily Goblin, Plundering Barbarian, Swarm of Goblins, Rapacious Dragon, Fissure Wizard, and Earth-Cult Elemental

There will likely come a board state where we'll have a couple goblins sitting around, unable to attack effectively. Well, the Predator here turns those useless tokens into a dead opponent, and does so with alacrity. Haste on this big beasty is such an incredible beating, and we won't need many goblins to eat or many turns to swing to end the game in our favor. 

A flavor homage, since I know it's a big spell in D&D. We'll mostly be using it as a "Crush Target Rare" removal spell, but there are several board states where we'll cast it for X = 2 or 3, and that will crumble the board in a way that lets us attack for huge gains. Perhaps not the most devastating damage spell imaginable, but in most games it will do more than enough and since we're playing a Mono-Red deck, the triple R in the casting cost isn't detrimental. 

Unsung Hero

I couldn't build this deck without including the best flavor hit in AFR! Because of Subira and the Smuggler, we'll be able to sneak in some damage. Because of the Battle-Cry Goblin and our various pump effects, we can get some inflated power, and the Critical Hit will drive that damage home. If we never hit the natural 20, it's still a fine combat trick that will either trade for an opposing creature or a big chunk of life total. If we get to do it twice? I smell a winning campaign. And in a D&D set, what's more appealing than that?