Seize Control precon upgrade guide

Mizzix discounts instants and sorceries and nothing else, and 22 of the box’s other nonland cards are neither. They average mana value 4.45, thirteen of them cost five or more, and the commander’s discount never reaches any of them.

Commander 2015 is the experience-counter set, and Mizzix’s counters pay out twice. Each one takes a generic mana off every instant and sorcery you cast, and you only gain one when the spell’s mana value is greater than the counters you already have. The first counter takes any spell. The third needs a three or better, and the fifth needs a five.

The box supplies plenty of fuel for that: 38 of the other 99 cards are instants or sorceries. What it doesn’t supply is a reason to cast the rest of the list. The 22 cards that pay full price include five creatures that never touch a spell, and everything else in this guide follows from separating the cards that feed the ladder from the cards that sit beside it.

Nothing here is a different deck. The twelve swaps add three more discounts, one source of free mana and four cheap answers, and take out the cards Mizzix can neither discount nor use.

What are the best Seize Control upgrades?

Ranked by how much they change a normal game:

1. Baral, Chief of Compliance, Archmage of Runes and Primal Amulet: three more cards that take {1} off every instant and sorcery, stacking with Mizzix, Goblin Electromancer and the counters. Archmage also draws a card per cast, and the Amulet flips into a land after four.
2. Storm-Kiln Artist: a Treasure every time you cast or copy an instant or sorcery, so a spell discounted down to nothing leaves you a mana ahead.
3. Steam Vents and Shivan Reef: two blue-red lands that can enter untapped, in place of two that can’t.
4. Lightning Bolt, Counterspell, Fire // Ice and Chaos Warp: four answers at one, two, two and three mana, which double as cheap rungs on the ladder.
5. Frantic Search: draw two, discard two, untap up to three lands.
6. Arcane Signet: a fifth mana rock next to Sol Ring, Izzet Signet, Thought Vessel and Worn Powerstone.

The twelve cuts are just below, after the reason most of them are cuts.

Twenty-two cards pay full price

Count the box’s nonland cards that aren’t instants or sorceries, leaving Mizzix out, and you get 22: fourteen creatures, five artifacts and three enchantments. Their average mana value is 4.45 and thirteen cost five or more. Seal of the Guildpact is the only card that discounts any of them.

Some of those earn the full price. Talrand makes a 2/2 Drake whenever you cast an instant or sorcery. Arjun swaps your hand for a fresh one on every spell, Melek lets you cast them off the top and copies the ones you do, and Charmbreaker Devils returns a random one every upkeep and gets +4/+0 when you cast one. Psychosis Crawler stays for a different reason: its power is your hand size and each opponent loses a life whenever you draw. Windfall, Jace’s Archivist and Dragon Mage refill the hand in one go, and Thought Reflection doubles every draw.

The rest are the problem. After the swaps the group is 21 cards with an average of 4.14, and ten cost five or more.

What leaves: five creatures, four spells, an enchantment and two lands

The creatures first, because none of them casts, counts or cheapens a spell:

• Warchief Giant: five mana, double red, a 5/3 with haste and myriad. It attacks, and that is all it does.
• Broodbirth Viper: a 3/3 for five that draws a card only if it connects with a player.
• Lone Revenant: a 4/4 hexproof for five whose card selection needs you to control no other creature. The first Drake from Talrand turns that off.
• Gigantoplasm: a copy of whatever creature is already on the table. A copy of your own Talrand, Arjun or Melek runs into the legend rule.
• Illusory Ambusher: a 4/1 with flash for five, and the cards it draws come from the damage that usually kills it.

Then four spells. Act of Aggression and Reins of Power borrow creatures until end of turn, and the deck has no sacrifice outlet to turn a borrowed creature into anything more than one attack. Reins of Power also hands your own creatures to the opponent for the turn. Word of Seizing can borrow any permanent and has split second, but that is a lot of mana for a trick this deck has no follow-up for. Mirror Match can only be cast in the declare blockers step, so it does nothing unless someone attacks you.

Awaken the Sky Tyrant is the enchantment. It costs four, is not a spell Mizzix can discount, and does nothing until an opponent’s source damages you, at which point it trades itself for a 5/5 flier. Izzet Guildgate and Swiftwater Cliffs are the lands, and they are replaced below.

Every counter needs a bigger spell than the last

By printed mana value the box’s 38 instants and sorceries run six at one, six at two, seven at three, ten at four, four at five, two at six and three at seven. Eight of them have an X in the cost (Epic Experiment, Meteor Blast, Repeal, Comet Storm, Magmaquake, Stroke of Genius, Dominate and Blue Sun’s Zenith). An X spell counts whatever X you chose while it is on the stack, so those eight can reach any rung you can pay for.

The swaps keep the ladder and change its shape. Four instants and sorceries leave (mana values 4, 5, 5 and 6) and five arrive at 1, 2, 2, 3 and 3, so the rungs now read seven, eight, nine, nine, two, one and three. The top does thin: spells at five or more fall from nine to six. I’m comfortable with that, because a sixth counter needs five good casts first, and Blatant Thievery, Call the Skybreaker, Firemind’s Foresight and Aethersnatch are still there at six and seven.

The discount trims generic mana only. Preordain and Brainstorm cost no generic mana, so nothing in the deck makes them cheaper, and Lightning Bolt and Counterspell join them. Bolt and Counterspell earn the slot as rungs and as answers, not as bargains. A card like Fact or Fiction ({3}{U}) is where the discount shows: with three counters and both Electromancer and Baral out, all three of its generic mana come off and it costs {U}.

One more consequence, and it favours the new cheap cards. Firemind’s Foresight fetches an instant at mana value 3, then 2, then 1. The adds give it cheap targets at every step: Frantic Search at three, Counterspell at two and Lightning Bolt at one.

Six tapped lands become four, and red needs less

Izzet Boilerworks, Izzet Guildgate, Spinerock Knoll, Swiftwater Cliffs, Vivid Crag and Vivid Creek all enter tapped. Steam Vents and Shivan Reef replace the Guildgate and the Cliffs, which leaves four. Steam Vents enters tapped unless you pay 2 life as it enters. Shivan Reef always enters untapped, but each coloured mana it makes deals 1 damage to you.

The colour demand moves too, without a single source added to fix it. Ten spells count as wanting a double red cast by turn three in the box, and seven do after the swaps, because Warchief Giant, Word of Seizing and Act of Aggression leave. Act of Aggression can pay its red with life and Call the Skybreaker’s hybrid symbols take either colour, so the true demand is a little lower than those counts. Blue falls from fifteen spells to fourteen: Lone Revenant, Mirror Match and Reins of Power leave, Archmage of Runes and Counterspell arrive. Arcane Signet lifts both colours from 23 sources to 24.

I didn’t trim the thirty-nine lands, though it is above the range most decks run. Call the Skybreaker has retrace, which casts it from the graveyard by discarding a land, eight X spells use every spare mana, and Temple of the False God needs five lands to work. If your hands flood, a basic is the first thing out.

One reconciliation with the summary at the top. It counts Primal Amulet’s back face as a land and a colour source, which you can’t use until the Amulet flips, so it reads 40 lands and 25 sources of each colour. Without it the deck has 39 lands and 24 sources, and the average mana value is about 3.5 either way.

The six and seven drops that stay

Several cards here look like cuts at a glance. Blatant Thievery costs seven and takes one permanent from each opponent for good. Aethersnatch costs six and takes control of a spell on the stack. Prophetic Bolt deals 4 damage to any target and digs four cards deep. Etherium-Horn Sorcerer has cascade, so it brings a free card with it, and it can bounce itself for {1}{U}{R} to do that again. Each one is a late rung on the ladder or a repeatable source of cards.

Seal of the Guildpact looks like a cut too, a five-mana artifact that does nothing on its own, and it stays for the reason in the FAQ: it discounts Mizzix himself. Storm-Kiln Artist isn’t a Wizard, which doesn’t matter: ten of the upgraded deck’s thirteen creatures are Wizards and no card in it checks for the type.

One skipped card needs naming. Cyclonic Rift is a Game Changer and costs about $30, which would nearly double the cost of this whole list.

The upgraded decklist

Hover or tap any card name to see it. Each price on the page is for whichever released printing of the card costs least, which can be a promo.

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“Load into the deck builder” opens this list in your account, pinned to the printings the box shipped, ready to edit or save. “Copy decklist” gives you plain text for Moxfield, Archidekt or Arena, with no account needed.

FAQ

Does Mizzix make Counterspell free?

No. Mizzix and every other discount in this deck take away generic mana only, never a coloured symbol. Counterspell costs {U}{U} and has no generic part, so it costs the same with five counters as with none. It earns its slot as a cheap rung on the experience ladder and as an answer you can hold up, not as a bargain.

Why is Cyclonic Rift not on the add list?

It is a Game Changer, and it costs about $30 at the cheapest printing (a 2XM copy, checked October 2026). One Game Changer rules out Bracket 2 and sets a Bracket 3 floor, and none of the twelve adds do that. If your table plays Bracket 3, it is the first card I would add, and its overload mode costs less with every counter Mizzix has.

Which two colours should Seal of the Guildpact name?

Blue and red. Each chosen colour a spell is takes one generic mana off it, so a single-colour spell gets one off and a blue-red one gets two. That covers Mizzix himself from the command zone (commander tax is added first, then the reduction applies), Arjun, Melek, Etherium-Horn Sorcerer and Call the Skybreaker. Unlike the other discounts in the deck it also works on creatures and artifacts.

Does Fire // Ice count as a four-mana spell?

It does everywhere except the stack. On the stack it is whichever half you cast, so both halves have mana value 2 and each costs {1}{R} or {1}{U} before discounts. That is why it counts as a two on the ladder. It also means Firemind’s Foresight can’t find it, because the tutor looks for instants with mana value 3, 2 and 1, and the whole card is a 4.

What do the twelve adds cost altogether?

The twelve adds come to $35.01, priced at the cheapest released printing of each, which can be a promo. Primal Amulet at $11.28 and Steam Vents at $9.57 are $20.85 of that. Star Trek puts a new Steam Vents in stores on 13 November 2026, so that is the add to hold off on.

Can I skip Steam Vents?

Yes, and it is the first add I would drop. Shivan Reef costs $0.18 and does the same job of replacing a tapped land, at 1 damage per coloured mana instead of 2 life once. What Steam Vents buys is less damage over a long game, and a price that should fall after the Star Trek reprint.