Mirror Mastery precon upgrade guide

Both of Riku of Two Reflections’ copy triggers cost blue to use, and blue is the colour this box has least of: 18 sources against 21 red and 28 green.

Riku copies an instant or sorcery you cast for {U}{R}, and makes a token copy of another nontoken creature entering under your control for {G}{U}. Blue is in both payments. So every copy Riku makes asks for a blue source on top of the card that triggered it, and the stock list is built as though it didn’t.

Commander 2011’s Temur deck has 41 lands, 28 of them basic, and eight of the other thirteen enter tapped. Its blue count is the lowest of the three colours, 18 sources. Meanwhile 23 of its non-land cards cost six or more, and the one card that sets its bracket floor, Ruination, destroys the nonbasic lands that fix the colours. This guide is mostly about turning that into a deck where Riku’s tax is one you can pay.

What are the best Mirror Mastery upgrades?

In this order:

1. Breeding Pool, Steam Vents and Frontier Bivouac replace Temple of the False God, Homeward Path and Fungal Reaches. All three make blue, and blue goes from 18 sources to 22. $19.06 for the three.
2. Cutting Ruination. It can destroy up to 13 of your own lands, and it is the reason the box starts at Bracket 4.
3. Cloudkin Seer, Mulldrifter, Coiling Oracle and Eternal Witness: four creatures that do something when they enter, which is exactly what Riku’s second trigger copies.
4. Pongify, Chaos Warp and Beast Within: three cheap answers for a box that ships with two pieces of spot removal, and the first trigger can double all three.
5. Fact or Fiction, Expansion // Explosion and Arcane Signet: a draw spell, a copy spell that works when Riku isn’t out, and a rock that makes all three colours.
6. Nine cuts from the top of the curve and the trick slots, argued below.

Thirteen cards leave and thirteen arrive. Prices are the lowest I found among released printings, promos included, as of October 2026.

Where the extra blue comes from

The box’s eight tapped lands are Gruul Turf, Izzet Boilerworks, Kazandu Refuge, Rupture Spire, Simic Growth Chamber and the three Vivid lands. Three of them are bounce lands, Gruul Turf, Izzet Boilerworks and Simic Growth Chamber, which return a land to your hand when they enter, so they make no mana on the turn they come down.

Breeding Pool and Steam Vents come in untapped for 2 life, and each makes blue plus one of the other two colours. Frontier Bivouac enters tapped and makes all three. With Arcane Signet in the list as well, the sources move like this:

• Blue: 18 to 22
• Red: 21 to 23
• Green: 28 to 30

A single blue pip by turn two goes from 81.2% to 87.7%. Two blue pips by turn three, which Conundrum Sphinx, Spell Crumple and Trench Gorger want, go from 51.5% to 63.9%, and that one stays low. The deck has a few cards that need UU, and reaching 90% for them would take 36 blue sources, which it can’t do without giving up red or green. I’m not trying to make them reliable. Several of the other blue cards, Call the Skybreaker and Nucklavee among them, take red mana for the same pips.

The three lands that leave are the ones that make no coloured mana when they come down. Temple of the False God needs five lands in play before it makes its two colourless, Homeward Path taps for one colourless, and Fungal Reaches makes colourless until you have spent turns storing counters on it to turn into red and green. The source counts on this page include it as red and green, which flatters the box.

Two cards stay out. Ketria Triome ($16.56) does what Frontier Bivouac does with cycling attached, and nothing in this list wants its land types. Stomping Ground ($7.17) would help red and green, which this list already has 23 and 30 sources of. If you own either, they go in the same slots.

Always-tapped lands go from eight to nine, because Frontier Bivouac is one. I’m accepting that, since it replaces a land that made no colour at all. The land count stays at 41, high for a list with 11 ramp spells. I left it there because every land cut would come out of a colour that is still short somewhere.

What Riku is worth paying for

The spell count doesn’t change: 23 instants and sorceries before and after, so five go and five arrive. What changes is how many of them are worth {U}{R}. Colossal Might, Invigorate and Ray of Command are one-creature effects, so doubling them doubles a trick. Pongify copies into a second dead creature, Chaos Warp into a second permanent shuffled away, and Beast Within into a second destroyed permanent. Pongify and Beast Within each leave the victim’s controller a 3/3, which is what you pay for the removal. Fact or Fiction reveals five cards a second time.

Two of the stock spells scale in a way worth knowing. The copy keeps the original’s X, and Savage Twister is X damage to each creature, so a copy means each creature takes it twice, yours included. Disaster Radius is the one-sided sweeper in the box. It deals damage equal to the mana value of the creature you revealed to each creature your opponents control, and that revealed card counts for the copy as well. Reveal Krosan Tusker and an {U}{R} payment makes 14 damage to each opposing creature across the two.

Explosion, the second half of Expansion // Explosion, scales the same way: X damage to any target and X cards drawn, both doubled. Expansion is the other half. It copies an instant or sorcery with mana value four or less for two hybrid mana, which is the price of Riku’s own trigger. The reason to play it is that it works without Riku, and it can copy a spell an opponent cast.

On the creature side, ten creatures now have an enters trigger, up from six. Mulldrifter draws two when it enters, so its token draws two more. If you evoke Mulldrifter for {2}{U} and pay {G}{U}, the token stays: it enters without its evoke cost paid, so nothing sacrifices it. Cloudkin Seer, Coiling Oracle and Eternal Witness copy for a card or a recursion each. Eternal Witness is the only one of the four that asks for GG.

Nine cards leave the top of the curve and the trick slots

Magmatic Force costs eight, Artisan of Kozilek nine and Hunting Pack seven. Hunting Pack makes a 4/4 Beast, plus another for each spell cast before it that turn. Artisan returns a creature from your graveyard when you cast it, and its annihilator 2 needs it to survive to attack. Nothing else in the box costs nine. Magmatic Force deals 3 damage at every upkeep, and its eight mana includes RRR. Red has 21 sources in the box, which gives two red pips by turn four a 67.3% chance. Across all 13 swaps the average mana value goes from 4.26 to 4.02, and cards costing eight or more go from four to two.

Colossal Might adds +4/+2 and trample for a turn, Invigorate adds +4/+4, and Ray of Command borrows an opponent’s creature for a turn. None of them draws, ramps or answers anything. The three Vows are politics auras: Vow of Flight and Vow of Lightning give +2/+2 and flying or first strike, Vow of Wildness gives +3/+3 and trample, and all three stop the creature attacking you. Nothing in a deck built on copying uses that.

Ruination is the one cut that changes the bracket. It destroys all nonbasic lands, and 13 of this deck’s 41 are nonbasic, including Command Tower. Without it the checker finds neither a Game Changer nor mass land denial, so its floor drops from 4 to 1. Faultgrinder stays, since its enters trigger destroys one target land and not all of them.

Cyclonic Rift ($28.93) would be the natural blue answer, and it is a Game Changer, which would put one in a list that has none. I left it out for that reason as well as price.

Four six- and seven-drops that work as lands

The box has 13 non-land cards at six mana. Four of its six- and seven-drops are fine because they can be cycled: Chartooth Cougar fetches a Mountain for {2}, Valley Rannet a Mountain or a Forest, Elvish Aberration a Forest, and once it’s on the table it taps for GGG, and Krosan Tusker cycles for a basic land and a card. They count against the spell total and then act as lands when the hand needs them, which is why I’m not cutting them for being six-drops.

The rest of the six-drops stay for a reason of their own. Deadwood Treefolk gets a creature card back from your graveyard on entering and again on leaving, so a Riku token of it returns two on the way in. Aethersnipe bounces a nonland permanent. Nucklavee gets back a red sorcery and a blue instant, and the new list has eight of each to find. Spitebellows deals 6 damage to target creature when it leaves the battlefield, including when evoked.

Four sweepers stay: Firespout, Chain Reaction, Savage Twister and Disaster Radius. Firespout, Chain Reaction and Savage Twister hit your own board too, and a deck with 27 creatures should be casting them as a reset and not a habit. Disaster Radius is the one that leaves yours alone.

Removal moves from two cards to four and draw from six to eight, both by the same count as the rest of this page. Removal is still short of the 5 to 10 that's typical. I stopped there because every new answer can be doubled by Riku, and a fifth would have meant cutting something that does a job.

The upgraded decklist

The list after all 13 swaps. Hover a card name to see it, and prices on the card are live.

Load into the deck builder Copy decklist Playtest the upgraded deck

“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

Why does the bracket floor drop from 4 to 1 after these swaps?

Ruination alone sets the box's floor. It destroys every nonbasic land, which the bracket rules treat as mass land denial and don't expect below Bracket 4. With it gone the list has no Game Changer and no mass land denial, so the floor is Bracket 1. A floor is the lowest bracket the list can honestly claim. It says nothing about where the deck plays.

How much blue does Riku need before the copies are worth paying for?

Every copy costs blue. The spell copy costs {U}{R} and the creature copy costs {G}{U}, on top of the card that started it. The box has 18 blue sources, which gives a single blue pip by turn two an 81.2% chance. The swaps take it to 22 sources and 87.7%. Reaching 90% would take 24, two more than the swaps get to.

Does Riku double a damage sweeper if he copies it?

Yes, and the X is copied too. A copied Savage Twister deals X to each creature twice, so a creature takes 2X in total, and that includes yours. Disaster Radius is the better candidate: it only hits your opponents' creatures, and the revealed creature card counts for the copy as well. Reveal Krosan Tusker (mana value 7) and the original and the copy deal 14 damage between them to each opposing creature.

Can a copy Riku makes set off Riku again?

No. A copy of a spell is put on the stack without being cast, so the first trigger doesn't see it. The second trigger only looks at nontoken creatures, so the token copy of Mulldrifter doesn't set it off either. Each cast spell or entering creature gets one payment and one copy.

Is Ketria Triome worth $16.56 here over Frontier Bivouac at $0.25?

Both enter tapped and both make green, blue and red. The Triome adds cycling for {3} and the Forest Island Mountain types, and nothing in this list searches for those types. Frontier Bivouac does the same mana job for the price of a bulk card. If you already own a Triome it goes in the same slot.

What will the upgrade set me back, and which prices could move?

$25.04 for the 13 adds at the lowest price among released printings, as of October 2026. Breeding Pool and Steam Vents are $8.97 and $9.84 of that, and both are being reprinted in Star Trek on 13 November 2026, so those two prices may move. Three of the thirteen cost under 20 cents.