Hi, I’m Jari Rentsch, founder of the Unity League and passionate MTG player. We recently launched new features on our website that let any player publish articles, with full integration for decklists and card links. To lead by example, I decided to write one myself.

I recently played Jeskai Prowess at the Mega Modern in Birmingham, a massive 185-player event hosted by Axion Now. After many friends asked for sideboard tips and advice, I figured I’d put together this article. It covers the sideboard plans I used throughout the event and some thoughts on how the deck matches up against today’s Modern metagame.

Whether you’re sleeving up Slickshot Show-Off or trying to beat it, I hope this guide helps.

Why splash white?

High Noon , Deafening Silence and Trinisphere are the best hate cards against Prowess. The Izzet build is quite soft against those hate pieces, as your only answers Spell Pierce and Into the Flood Maw are very conditional. Prismatic Ending is an easy way to answer those hate pieces, that still kills a creature in the absence of them. The splash is also very light, as Wear // Tear can often be played with red mana only.

More Speed!

As much as I dislike playing Violent Urge against midrange decks, I feel it's just necessary to play 3 copies of this card to keep up with the incredible velocity of the Modern format. Consequently I trimmed down to 3 copies of Expressive Iteration , but cutting more of them feels risky as you still need sorceries to enable delirium.

Sideboard Guide

In the following I provide a generic sideboard guide that works for various versions of Izzet and Jeskai Prowess. 

Boros Energy

• Out: 3 Violent Urge , 1 Mutagenic Growth , 2 Preordain
• In: 3-4 Unholy Heat / Prismatic Ending , 1-2 Abhorrent Oculus , 2 grave hate (e.g. Tormod's Crypt , Soul-Guide Lantern , Surgical Extraction )

In theory this match up feels favored for Prowess, as you can efficiently deal with individual threats, making it difficult for the opponent to establish their key synergies like Guide of Souls plus Ocelot Pride , or Ajani, Nacatl Pariah // Ajani, Nacatl Avenger alongside Goblin Bombardment . However Phlage, Titan of Fire's Fury can be a big issue in the late game and Boros Energy strong sideboard hate against us in the form of Deafening Silence or High Noon .

Post-board, Boros often transitions into a control role, and the games typically hinge on whether you can shut down Phlage, Titan of Fire's Fury with timely graveyard hate. This is also where the white splash proves most valuable. Prismatic Ending deals with hate pieces like High Noon , but it's never a dead card, as it can always answer an early threat like Guide of Souls .

Mirror (Prowess)

• Out: 3 Expressive Iteration (Draw: 1 Cori-Steel Cutter )
• In: 3-4 Unholy Heat / Prismatic Ending / Into the Flood Maw

The mirror is a race, most games are decided by turn 3 so we only side in efficient removal to tip the scales. Into the Flood Maw might seem odd, but bouncing a Slickshot Show-Off or a target of Violent Urge can often turn around the race, especially since all the other removal spells fold to a Mutagenic Growth .

Amulet Titan

• Out: 3 Expressive Iteration , 2 Lava Dart , 2-4 Cori-Steel Cutter
• In: 3-4 Consign to Memory , 2 Wear // Tear , 2-4 Unholy Heat / Prismatic Ending / Into the Flood Maw

You need to apply fast pressure while keeping up interaction, which makes clunky cards like Cori-Steel Cutter and Expressive Iteration too slow.

Consign to Memory can counter Amulet of Vigor and it's triggers to untap lands. Likewise it counters the search triggers from Urza's Saga and Primeval Titan , disrupting their engine entirely.

Unholy Heat cleanly answers Primeval Titan , while Prismatic Ending takes care of Amulet of Vigor and the annoying blocker Arboreal Grazer .

A timely Into the Flood Maw can blow out their turn by bouncing a Spelunking , Amulet, or even a Titan before it's being copied or can attack with haste.

Eldrazi

• Out: 3 Expressive Iteration , 4 Cori-Steel Cutter , 2 Lava Dart  
• In: 4 Consign to Memory , 2 Spell Pierce , 2 Prismatic Ending / Into the Flood Maw , 2 Wear // Tear

The biggest threat in this matchup is an early Trinisphere , if it resolves unchecked, you often lose on the spot. If you don’t draw direct removal, you will always need to hold up one mana for Spell Pierce or Consign to Memory to counter it. This requirement makes it almost impossible to fit Cori-Steel Cutter and Expressive Iteration into your curve. Don't forget that Wear // Tear can kill an Utopia Sprawl and a Trinisphere for just 3 mana.

Blue Belcher

• Out: 3 Expressive Iteration , 2 Cori-Steel Cutter , 1 Lava Dart
• In: 4 Consign to Memory , 2 Spell Pierce

You need to hold up mana for their combo, so clunky cards like Expressive Iteration and Cori-Steel Cutter have to go. Consign to Memory counters Goblin Charbelcher or the cast trigger of Lotus Bloom . 

Dimir Murktide

• Out: 3 Violent Urge , 4 Mutagenic Growth (1 Lava Dart )
• In: 2-3 Unholy Heat , 2 Prismatic Ending / Into the Flood Maw , 2 Spell Pierce , 1 Abhorrent Oculus

Cori-Steel Cutter is actually your best card here and you’re happy to delay it a turn or protect it with Spell Pierce to play around Counterspell .

You board out pump spells and bring in bounce and removal to be better prepared for longer games.

Domain Zoo

• Out: 3 Violent Urge , 3 Lava Dart , 3 Expressive Iteration
• In: 2-3 Consign to Memory , 3-4 Unholy Heat / Prismatic Ending , 2 Wear // Tear / Into the Flood Maw , 1 Abhorrent Oculus

Consign to Memory can counter key cards like Leyline Binding and Scion of Draco , but Wear // Tear is even better as it destroys them directly and also answers Leyline of the Guildpact . 

Storm

• Out: 3 Expressive Iteration , 1 Cori-Steel Cutter (Draw: 3 Cori)
• In: 2 Spell Pierce , 2 grave hate, (Draw: 2 Prismatic Ending / Into the Flood Maw )

On the draw, this matchup is tough, you need to kill by turn 3 while disrupting their combo, so most Cori-Steel Cutter copies have to come out.

Orzhov Ketramose

• Out: 3 Violent Urge , 4 Mutagenic Growth , 1-2 Lava Dart
• In: 3-4 Consign to Memory , 3-4 Unholy Heat / Prismatic Ending / Into the Flood Maw , 2 Wear // Tear , 1 Abhorrent Oculus

Consign to Memory shines here — it can counter the exile trigger from Solitude , saving key threats like Slickshot Show-Off . It also stops permanents from returning via triggers from Flickerwisp or Phelia, Exuberant Shepherd . You cut pump spells due to their effective instant speed interaction and lean on removal plus tempo plays.

Azorius Affinity

• Out: 4 Lava Dart , 1-2 Mutagenic Growth
• In: 3-4 Unholy Heat / Prismatic Ending , 2 Wear // Tear

Affinity has an incredible late game, so you both need to grind well but also kill quickly. They don't have a lot of instant speed interaction, so Violent Urge can be quite effective.

Living End

• Out: 4 Lava Dart , 3 Expressive Iteration (Draw: 1 Cori-Steel Cutter , Play: 1 Mutagenic Growth )
• In: 4 Consign to Memory , 2 grave hate, 2 Spell Pierce

Living End is an easy match up, as long as they don't resolve their namesake card. Hence you again need to focus on keeping up one mana to counter their cascade triggers.

Neobrand

• Out: 3 Expressive Iteration , 2 Cori-Steel Cutter
• In: 2 Spell Pierce , 3 Consign to Memory , (or 2 Into the Flood Maw instead of Consign)

Neobrand really folds to a single Spell Pierce , but otherwise there's not much we can do. Luckily their deck is quite fragile, so countering a trigger from Ghalta, Stampede Tyrant or bouncing a creature can sometimes be enough to make them die from their Summoner's Pact .

Thanks for reading! I hope this guide helps you pilot Prowess or beat it. If you have thoughts, questions, or want to share your own take, feel free to reach out. And if you’d like to publish your own article on the Unity League site, get in touch!

📧 jari@unityleague.gg

🐦 @tiray_7