Precon Upgrade Guide
Arcane Maelstrom Upgrade Guide
What to cut, what to add, and how to play the Temur instants precon from Commander 2020, commanded by Kalamax, the Stormsire.
Commander 2020
Arcane Maelstrom
Copying spells off Kalamax is strong but timing-dependent. Out of the box, before any upgrades. How we rate precons
Buy Arcane Maelstrom on TCGplayer →Quick verdict
Arcane Maelstrom is one of the stronger Commander 2020 decks, built around copying instants on every player's turn. Kalamax, the Stormsire copies the first instant you cast each turn as long as it is tapped, and grows with every instant you copy. The catch is getting Kalamax tapped without sending it into combat, which the box barely addresses. It also spends slots on goad auras and expensive creatures that do nothing with instants, and its mana base enters tapped far too often.
TurnZero HQ rates Arcane Maelstrom a 3 out of 5 on difficulty and a 4 out of 5 on power, as it comes in the box. That is our editorial read, not an official Wizards rating. The full hundred cards are on the Arcane Maelstrom decklist page, and every other precon we cover is on the precon directory.
How the precon plays
Kalamax, the Stormsire copies the first instant spell you cast each turn, but only if Kalamax is tapped when you cast it. The copy can take new targets. Whenever you copy an instant spell, from Kalamax or anything else, Kalamax gets a +1/+1 counter. Because the trigger checks each turn, a tapped Kalamax can copy one instant on your turn and one on each opponent's turn.
The simplest way to tap it is to attack, which leaves Kalamax tapped through the opponents' turns that follow. The deck then holds up instants like Prophetic Bolt , Chaos Warp and Temur Charm and gets two of each. Lightning Greaves gives Kalamax haste so it can attack the turn it comes down.
The rest of the deck stacks more copying on top. Twinning Staff adds an extra copy whenever you copy a spell, Swarm Intelligence and Melek, Izzet Paragon copy instants and sorceries, and Dualcaster Mage copies one at instant speed. Talrand, Sky Summoner , Murmuring Mystic and Lunar Mystic turn each instant into a flier or a card.
What works out of the box
Kalamax, the Stormsire ↗
Copies the first instant each turn while tapped, on every player's turn, and gets bigger with every copy. Each instant in hand is worth two.
Twinning Staff ↗
Every time you copy a spell you get one more copy. With Kalamax out, the first instant each turn resolves three times.
Talrand, Sky Summoner ↗
A 2/2 flying Drake for every instant or sorcery you cast. Copies don't count as casts, but the deck casts enough instants that the Drakes pile up anyway.
Temur Charm ↗
Three modes in Kalamax's exact colors: a fight, a soft counterspell, or an alpha strike. Copied, it can counter a spell and set up a fight at once.
Prophetic Bolt ↗
Four damage to any target plus a card from the top four. With a copy you get eight damage and two picks.
Wilderness Reclamation ↗
Untaps all your lands at your end step, so you spend your own turn developing and still have full mana for instants on opponents' turns.
What needs improvement
Kalamax only works when it is tapped, and the box gives you almost no way to tap it except attacking. A 4/4 swinging into a table of blockers can die in combat, and on the turn you cast it, it can't attack without Lightning Greaves . Cards that tap Kalamax for value, like mana abilities, fix this directly.
Several slots don't touch the plan. Psychic Impetus , Shiny Impetus and Predatory Impetus are goad auras, Hunting Pack and Ravenous Gigantotherium cost seven mana each, and Curious Herd depends on how many artifacts an opponent happens to have. The mana base has more than a dozen lands that enter tapped, which fights against holding up instants.
Upgrade ideas
Each upgrade below starts from something the deck does poorly and says what a replacement card has to do. The cards named are examples, not the only answer: if you own something else that does the same job, or a newer printing does it better, it goes in the same slot. Make one change at a time and play a few games between them, so you can tell which change helped. The general method is in how to upgrade a Commander precon →
1. Tap Kalamax without attacking
Kalamax's copy only happens while it is tapped. If you can tap it for mana, you get the copy without risking it in combat, and the mana goes toward the instant you are copying.
What to look for Cheap cards that let a creature tap for mana or another effect. Anything that turns Kalamax's tap into value while keeping it home works.
Cut, for example
Psychic Impetus A goad aura that pumps an opponent's creature to send it at someone else. It has nothing to do with instants.
Predatory Impetus Five mana for another goad aura. Expensive, and it competes with the instants you want to hold mana for.
Shiny Impetus The Treasure is nice, but the aura still makes an opponent's creature bigger and doesn't help Kalamax.
Add, for example
Springleaf Drum ↗
One mana: tap the Drum and an untapped creature you control to add one mana of any color. Tapping Kalamax this way turns on its copy and pays toward the instant.
Paradise Mantle ↗
Zero to cast, equip {1}, and the equipped creature taps for a mana of any color. On Kalamax it does the same job as the Drum.
Cryptolith Rite ↗
Every creature you control taps for one mana of any color, including Kalamax and the Drake and Bird tokens the deck makes.
2. Add cheap instant-speed answers
Every instant answer Kalamax copies handles two problems. The box has some, but cheap counterspells and catch-all removal fit better than situational cards.
What to look for Instants costing three mana or less that counter a spell or remove any permanent. Targeted spells gain the most from a copy, since the copy can pick a new target.
Cut, for example
Curious Herd Makes 3/3s equal to the artifacts one opponent controls. Against a table with few artifacts it does almost nothing.
Eon Frolicker A 5/5 flier that gives an opponent an extra turn when it enters. The protection helps, but handing a player a whole turn is a steep cost.
Add, for example
Counterspell ↗
Two mana to counter any spell. A copy can counter a second spell on the stack.
Beast Within ↗
Destroys any permanent and leaves its controller a 3/3 Beast. A copy takes out a second threat.
Pongify ↗
One mana to destroy a creature, with a 3/3 Ape left behind. Cheap enough to cast alongside another instant in the same turn.
3. Swap the seven-drops for instant card draw
The deck runs out of instants in long games, and every copy of a draw spell is free cards. The seven-mana creatures are the easiest slots to give up.
What to look for Instants that draw two or more cards for four mana or less. Spells whose extra costs aren't paid again on a copy are especially good.
Cut, for example
Hunting Pack Seven mana for a 4/4 Beast plus storm copies. The deck rarely casts enough spells in one turn to make it worth the cost.
Ravenous Gigantotherium Seven mana and it needs creatures to devour. It is a creature, so Kalamax never copies it.
Add, for example
Brainstorm ↗
One mana to draw three and put two back. A copy draws three more, which lets you keep the best of a large pile.
Big Score ↗
Discard a card to draw two and make two Treasures. A copy doesn't require another discard, so you get four cards and four Treasures.
Fact or Fiction ↗
Reveals five cards and you keep one pile. Copied, it digs through ten cards at instant speed.
4. Untap the mana base
An instant deck wants mana open on other players' turns. Lands that enter tapped or need extra mana slow down the early turns when Kalamax needs to come down and get going.
What to look for Two-color lands in blue, red and green that enter untapped most of the time.
Cut, for example
Scavenger Grounds Taps only for colorless, and its graveyard exile is a narrow effect that costs you the land.
Rupture Spire Enters tapped and costs {1} on top of that or you sacrifice it. It sets you back a full turn of mana.
Add, for example
Win conditions
Most games are won by a large Kalamax and a board of fliers. Every copied instant adds counters to Kalamax, the Stormsire , Talrand, Sky Summoner and Murmuring Mystic fill the air with tokens, and a doubled Comet Storm or Prophetic Bolt finishes players off. The upgrades let you tap Kalamax safely with Springleaf Drum or Cryptolith Rite and keep enough instants flowing to copy one every turn.
Who should buy this precon
A good match for a player who enjoys holding up mana and acting on other players' turns. Tracking when Kalamax is tapped and which instant to save for a copy takes some thought, so it suits someone with a few games behind them rather than a first-timer. It is one of the stronger decks in its product line and rewards a player who plans a turn ahead.
Checked against the printed decklist on October 10, 2026.
Track how the upgrades actually perform.
TurnZero HQ keeps a win rate per deck version, so you can change a few cards, play some games, and see the difference instead of guessing.
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