Combo · ENGINE

A 0 Might body can hold, and 143.2.a still charges the attacker a point of damage to remove it

6 cards · calm · verified

Pieces

• Scuttle Crab ×3 UNL-053 · payoff · calm

  (Units with 0 Might can conquer and hold.) When you play me, draw 1. [Deathknell][>] Choose an opponent. They reveal their hand. You can look at their facedown cards this turn. Gain 1 XP. (When I die, get the effects.)

• Mutated Mouser ×3 UNL-036 · engine · calm

  [Shield 2] (+2 Might while I'm a defender.) [Tank] (I must be assigned combat damage first.)

Payoff

Deck

• Both cards are mono-Calm, so 103.1.b.3 admits any legend with Calm in its pair.
• Neither card is banned or restricted in either format, and neither is a Signature card.
• Both bodies at the same battlefield - 815.1.b orders the assignment only among units the SAME player controls.

Prerequisites

• A 0 MIGHT BODY IS NOT A DEAD BODY, AND THE CARD PRINTS THE RULE. Its own parenthetical is '(Units with 0 :rb_might: can conquer and hold.)', so the Crab takes and keeps a battlefield exactly like any other unit - 469.1 gains the Conquer, 315.2.b.2 Holds it. And 143.2.a needs marked damage AT OR ABOVE Might to kill, which still means NONZERO damage: a 0 Might body costs the attacker one point of their assignment, and 465.2.c.4 caps that at the minimum lethal, so it is one point and no more. Two Energy to make an attacker spend a point and to keep a battlefield.
• THE TANK IS WHAT KEEPS IT ALIVE, AND IT IS ONE MIGHT BIGGER THAN IT LOOKS. 815.1.b: the Mouser 'must be assigned lethal damage before any other unit with the same controller as me that does not have [Tank] during the Combat Damage step', and 815.1.c.2 makes every non-Tank body an invalid assignment until it has. 814.1.c makes [Shield] 'While I am a defender, I have +X [M].', so the printed 1 reads 3 on defence - the same designation-conditional Might this catalogue records in both directions. An attack summing less than 3 therefore kills NOTHING at that battlefield, and the Crab holds.
• AND THE CRAB'S DEATHKNELL IS THE POOL'S ONLY LOOK AT A FACEDOWN CARD. Swept: `grep -in facedown data/corpus_flat.txt` returns four rows - OGN-101 Mushroom Pouch (draws if YOU control a facedown card), OGN-181 Pack of Wonders (returns a friendly facedown card to hand), UNL-014 Monster Harpoon (a condition on your own) and UNL-053 Scuttle Crab. Only the Crab reads the OPPONENT's. 811.1.b hides a card facedown 'for as long as you control that battlefield' and the whole [Hidden] package is priced on that information asymmetry; this is the one card in the pool that removes it, and it does so for the whole turn.
• IT ALSO PAYS ON BOTH ENDS, WHICH IS RARE AT TWO ENERGY. 'When you play me, draw 1' on the way in, and on the way out a hand reveal plus 1 XP - and 808.1.c makes the Deathknell 'functionally short for "When I die, [Effect]"'. 808.1.d.1 is the one thing that switches it off: a heal / exhaust / recall shield means it never reaches the Trash and 'the triggered ability will be removed from the chain'. Do not protect this body; it is meant to die.
• THE XP IS A RIDER, NOT A PLAN. One per Crab, three by 103.2.b - enough to switch on a [Level 3] such as UNL-047 Mosstomper's, and nowhere near the [Level 6] rungs in the same domain. mosstomper-wuju-apprentice-xp-calm-ladder is where that ladder is walked; this is a supplementary faucet and the entry says so rather than pretending otherwise.
• WHAT IT IS NOT. The Crab's own Conquer or Hold scores by 469.1 and 471.1, but neither card in this entry causes one that would not have happened - what they buy is the ability to KEEP a battlefield cheaply.
• ONE ENERGY AT REACTION SPEED ANSWERS THE BODY THIS ENGINE STANDS ON (Scuttle Crab (M0 x3); Mutated Mouser (M1 x3)). OGN-133 Flurry of Blades is Body, 1 Energy: "[Reaction] (Play any time, even before spells and abilities resolve.) Deal 1 to all units at battlefields." 143.2.a kills a unit whose marked damage equals or exceeds its Might and 142.4.b defines Lethal Damage as "a non-zero amount greater than or equal to that Unit's Might", so one damage is lethal to every body of Might 1 or less. RUNNING MORE COPIES IS NOT A DEFENCE: 370.1.a.2 makes events simultaneous when they "are all the result of the same Game Action", so the sweep kills every copy at once. And because it carries [Reaction], 813.1.c.1 lets it be played "during Closed States on any player's turn" - it never has to be cast a turn early the way the base-reaching removals do, and it can land in response to the very trigger this engine exists to fire. WHAT PROTECTS IT: this entry's cards are calm, so the second domain is still free and CHOOSING IT DECIDES WHICH PROTECTION YOU GET - 103.1.b allows exactly one partner, so these are alternatives and not a list you can run together. only if the second domain is FURY: VEN-018 Rage Amplifier (gear, 'Your units have +1 Might' - the only UNCONDITIONAL board-wide one, +2 while Empowered) | only if the second domain is ORDER: OGN-243 Darius, Executioner ('Other friendly units have +1 Might HERE' - his battlefield only, and never himself); OGS-013 Garen, Commander (same clause as Darius, same limits) | only if the second domain is MIND: UNL-077 Soul Shepherd ('Your TOKEN units have +1 Might' - tokens only, nothing for a printed body); SFD-089 Rumble, Scrapper ('Your MECHS have +1 Might' - Mech tag only) | colourless, so legal whatever the second domain is: OGN-294 Trifarian War Camp (colourless battlefield, 'Units here have +1 Might') - but 485.5 makes a battlefield you bring a 1-in-3, and 103.4.c forbids two of the same name. A single-target pump is no use against a sweep that hits every body at once, which is why only permanent, board-wide sources are listed.

Steps

1. Play Mutated Mouser (2 Energy) and Scuttle Crab (2 Energy); the Crab draws a card as it lands.
2. Send both to the same battlefield. 815.1.b orders the assignment among units you control, so they have to share a location.
3. The Crab can take and keep the battlefield despite having 0 Might - its own reminder text says so, and 469.1 with 315.2.b.2 do the rest.
4. On defence, 814.1.c makes the Mouser a 3 and 815.1.c.2 makes it the only legal assignment until it has lethal - an attack summing less than 3 kills nothing.
5. When the Crab does die, its Deathknell reveals the opponent's hand and lets you look at their facedown cards for the turn (808.1.c), plus 1 XP.
6. Do not shield the Crab: 808.1.d.1 removes the trigger from the chain if it never reaches the Trash.

Per iteration

a card on the way in, a full hand reveal plus every facedown card on the way out, and a battlefield held by two 2-Energy bodies

How it ends

engine only - three of each card by 103.2.b, and the Mouser's wall is 3 damage tall; nothing here scores beyond the Conquer or Hold the Crab was making anyway

Sources

Published elsewhere

• Riftbound Core Rules, Last Updated 2026-07-16 (data/Riftbound-Core-Rules-2026-07-16.txt) 2026-07-16
• Card text verbatim from data/corpus_flat.txt (built from Riot's gallery content API) 2026-09-07

Walked here, in this project

• Hand walk 2026-09-07 (docs/phase0/walks/2026-09-07-uncatalogued-calm-mind-order.md, batch 6) 2026-09-07 record

Walked against Core Rules 2026-07-16

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