Pauper: Boros Synthesizer (2025) - Deck Tech & Sideboard Guide

With the latest Banned and Restricted update, Pauper has undergone considerable changes that are leading players to explore new possibilities and revisit old archetypes to evaluate their viability in the new Metagame.

One of these decks is the Boros Synthesizer, a strategy that has existed in the format since 2015 and has undergone several changes in the last ten years: from versions with Palace Sentinels to more aggressive lists with All That Glitters, including the current iterations with Experimental Synthesizer and Makeshift Munitions — a variant that achieved two places in the Top 8 of the Challenges in the first week after the bans on Magic Online.

In this article, we explore this version of one of the most famous decks in Pauper history, with a Sideboard guide for the current Metagame!

This is the standard decklist that has been played since the last bans in Pauper, and it doesn't differ that much from what we saw in Boros Synthesizer before the update. As the format opens up, I believe that some absolute numbers will need to solidify or make room for other cards — for example, if Bogles grows too much, cards like Standard Bearer or Patrician's Scorn will become more necessary, and the same goes for all archetypes in the new Metagame.

Boros Synthesizer is a classic synergistic Midrange: you want to play cheap creatures and cards with efficient ETB effects and reuse them with Glint Hawk and Kor Skyfisher to generate card advantage. Its origins date back to when Faeries was the best deck in the format at the time and the archetype — once called Kuldotha Boros due to the use of synergy between Ichor Wellspring and the now banned Kuldotha Rebirth — was born to combat it.

As its history indicates, this archetype has a favorable and/or balanced matchup against Faeries. In addition, it handles most traditional Aggro decks well and can interact against Affinity and Tolarian Terror lists.

On the other hand, it suffers considerably against non-interactive strategies such as Walls, Dredge, Familiars and High Tide, as well as archetypes that can play over it, such as Tron — its natural predator since 2017 — and Gruul Ramp, whose addition of Writhing Chrysalis made the matchup even worse for Boros Synthesizer.

Maindeck

Glint Hawk and Kor Skyfisher are our main means of reusing the ETB effects of our creatures and artifacts. In addition, they are our main beatdown because they are low-cost creatures with evasion.

Thraben Inspector and Novice Inspector are one-drops that put artifacts into play to enable Galvanic Blast's Metalcraft and ensure card advantage in longer games.

Due to the nature of the format and how Boros has needed to be faster while giving up cards like Prismatic Strands, it's possible to consider Voldaren Epicure in one of these slots to complement Makeshift Munitions in the direct damage plan at the expense of less resilience in blocking — less important now that Kuldotha Rebirth is no longer in the format.

Experimental Synthesizer was the most important addition to Boros in recent years, to the point of changing the deck's name. It does everything the archetype wanted with Ichor Wellspring for one less mana, allowing for more efficient lines with Kor Skyfisher and Glint Hawk.

Lembas was another upgrade of the artifacts with ETB that made a big difference in the Synthesizer lists. In addition to guaranteeing topdeck filtering, it can also be sacrificed to gain life and hold the Aggro beatdown for a few turns.

Lightning Bolt and Galvanic Blast are Pauper's primary means of interaction today, and double as a means of increasing the pressure we can exert on Boros. Since we draw a lot of cards, setting up in our hand to bring the opponent's life to a point where our Burns end the game is a very common line.

Thraben Charm offers many options in a single slot: an answer to enchantments — less important without Broodscale Combo, but still essential against Bogles or Gruul Ramp —, graveyard hate, and removal that even deals with Myr Enforcer if its controller has two or more creatures in play. I don't know if three slots are what the deck needs today, but it's a good start.

Journey to Nowhere is less flexible than the other removals, but it works as the main way to deal with Tolarian Terror and Cryptic Serpent, without giving up utility against other creatures in the current Metagame.

The “flex” slots.

Relic of Progenitus in the maindeck can be any other artifact, but I'm in favor of ​​having four hates in Game 1 against Tolarian Terror and also a way to break the loops of High Tide that usually require Flood of Recollection and/or Stream of Thought returning several cards to the deck at some point to close the combo.

Makeshift Munitions makes sense in an archetype where we have many artifacts and creatures, it controls the board almost permanently against several X/1s in play, such as against Faeries, and it works as another win condition with Burn spells.

Eight artifact lands are enough for the interactions we seek with them, so we can dedicate the tapped land slots for more flexible cards, and since Boros Synthesizer needs to be more proactive than in the past, Abraded Bluffs is our choice as it deals damage to the opponent when it enters.

To complement it, Boros Garrison reuses ETB effects during the turns, an interaction that also has with Radiant Fountain for games against Aggro.

Sideboard

Answers against Affinity.

This deck would never have a fair chance against an archetype that generates card advantage much faster and with a much more efficient clock without attacking your primary resource.

Dust to Dust is our best option in the play to deal with Affinity and maintains its usefulness even on the draw to force two-for-one effects against the opponent's main cards.

Cast into the Fire complements this game plan, giving us the ability to exile troublesome lands and artifacts on the second turn. In addition, its damage mode is useful against Faeries and Elves.

Speaking of Faeries, we have a full set of Pyroblast and a copy of Red Elemental Blast for games against blue decks, which also include Blue Terror, Tron, Familiars, and others.

Five of the same effects may seem like overkill — maybe it is — but they are our best chance against High Tide, which has obviously been popular due to the hype surrounding its unban.

Two more copies of Relic of Progenitus provide more resilience against Dredge, Blue Terror, and also come in against High Tide. You can add it against Affinity if you want to respect Blood Fountain a lot, but the fact that it doesn't provide ETB value, and we already have Thraben Charm, makes it redundant.

Navigator's Compass is the interaction choice against Red Aggro now that they have less permanent power. Reusing it with Glint Hawk or Kor Skyfisher already guarantees six life for a low cost and puts the opponent in a tough spot, especially if combined with Lembas and Radiant Fountain

Affinity

IN

OUT

Recent versions of Affinity have given up Kenku Artificer and taking a Reckoner’s Bargain in response to Journey to Nowhere is unpleasant, but being able to reuse it with Kor Skyfisher when this happens and having the security of being able to deal with the indestructible lands if they are turned into creatures, make them worth the maindeck.

If you are certain that your opponent is not playing Kenku Artificer, you can swap some Lightning Bolt for Journey to Nowhere.

Faeries

IN

OUT

Regardless of the version, mana efficiency is key in this matchup, so removing cards with higher mana value and/or sorcery speed in favor of instant interaction is our best route to keep the pressure on the board while responding to the opponent.

High Tide

IN

OUT

This matchup demands impeccable timing on responses, and keeping Thraben Charm mana untapped to deal with the graveyard is a bad choice. Keep in mind that some lists run Murmuring Mystic in games two and three, and it needs to be responded to immediately, or it will take over the game.

Synthesizer Burn

IN

OUT

There’s not much to say about this matchup. Use removals and blockers to hold the clock, put Lembas and Navigator’s Compass into play, and start looping with Kor Skyfisher and Glint Hawk to stabilize the board.

Gruul Ramp

No changes. Our sideboard is not well-prepared for this matchup, and our best route is to apply pressure while responding to the cards that prevent us from attacking through the air.

Blue Terror

IN

OUT

The biggest challenge in this matchup is against the Dimir versions that have enough removal to delay their clock since we have few of them in our list, and we also removed the Makeshift Munitions as they are easy targets for Hydroblast.

Elves

IN

OUT

It's important to know who your primary targets are in this matchup: Wellwisher, Priest of Titania and Timberwatch Elf are the cards that can win the game, so focus your spot removals on them.

Boros Synthesizer

IN

OUT

This side-in only works if your opponent has Bridges in their list. With variants like ours, it's best not to make any changes because our sideboard doesn't have many answers for this matchup, and Dust to Dust becomes much more conditional when we only have eight artifact lands to attack.

That's all for today!

If you have any questions, feel free to leave a comment!

Thanks for reading!