Combo · ENGINE

Fox-Fire's four-body ceiling is a fact about FLOORED reducers — 143.2.b makes an unfloored one cost the sum nothing

9 cards · calm + mind · verified

Pieces

• Fox-Fire ×3 OGN-256 · payoff · calm/mind

  [Hidden] (Hide now for 1 Power of any domain to react with later for 0 Energy.) [Action] (Play on your turn or in showdowns.) Kill any number of units at a battlefield with total Might 4 or less.

• Frigid Touch ×3 SFD-066 · engine · mind

  [Reaction] (Play any time, even before spells and abilities resolve.) [Repeat] 2 Energy (You may pay the additional cost to repeat this spell's effect.) Give a unit -2 Might this turn.

• Moonlight Affliction ×1 UNL-066 · engine · mind

  [Reaction] (Play any time, even before spells and abilities resolve.) Give a unit -10 Might this turn.

• Thousand-Tailed Watcher ×1 OGN-116 · engine · mind

  [Accelerate] (You may pay 1 Energy + 1 Mind Power as an additional cost to have me enter ready.) When you play me, give enemy units -3 Might this turn, to a minimum of 1 Might.

• Nine-Tailed Fox ×1 OGN-255 · legend · calm/mind

  When an enemy unit attacks a battlefield you control, give it -1 Might this turn, to a minimum of 1 Might.

Payoff

Deck

• OGN-256 Fox-Fire is a SIGNATURE card tagged Ahri, so 103.2.d.2 forces a Ahri legend that also covers calm + mind: OGN-255 Nine-Tailed Fox — the only one. Domain-legal legends without the Ahri tag cannot run the list. (Rebuilt from the census by test/legend-lines.test.ts, 2026-09-07; an earlier line named legends that cannot hold a Ahri Signature card.)
• Nothing enters the board except the Watcher in its own row; the Frigid Touch and Moonlight Affliction rows are all spells.

Prerequisites

• THIS ENTRY EXISTS BECAUSE A VERIFIED CEILING IS SCOPED AND ISSUE #97 DID NOT NOTICE THE ENTRY IT IS IN. ahri-foxfire-might-threshold ends on 'FOUR units at 1 Might sum to exactly 4, and that is the largest sweep THIS LINE can ever make.' That is true of that line, whose two reducers (OGN-119 Ahri, Inquisitive and the legend) both print 'to a minimum of 1'. It is not a fact about Fox-Fire. 143.2.b: 'If a unit's Might is ever less than 0, it is treated as 0 when referenced by spells and abilities' — and Fox-Fire's 'total Might 4 or less' is a spell referencing Might. An unfloored reduction therefore costs the sum NOTHING, where a floored one always costs at least 1. 143.2.b had ZERO citations in the whole catalogue before this walk.
• HOW THE SUM IS READ. 355.11: 'Some cards identify a group of Targets with Targeting Requirements that must be met by the group as a whole'; 355.11.a: 'such cards can choose any group of valid targets that collectively fulfill the targeting restriction'. 710: 'Units on the board are evaluated according to their current Might.' And the boundary nobody should reach for: 142.4.b makes lethal damage on a 0 Might body require 'at least 1 damage marked on it' — irrelevant here, because Fox-Fire KILLS, it does not deal damage.
• THE WATCHER ROW OF ISSUE #97 IS BACKWARDS AND THIS IS THE CORRECTION. The issue says four bodies 'de cualquier tamano' are flattened to 1 each. 477.3.b's own worked example says otherwise: "If an effect gives a unit '-4 [M] to a min of 1 this turn' choosing a unit with 2 [M], then the effect will generate -1 [M] this turn." The floor limits the SIZE OF THE REDUCTION, not the resulting Might, so '-3 to a minimum of 1' maps M to max(1, M-3) and a 10 Might body lands on 7. The honest budget against Fox-Fire's 4: four bodies of M4 or less (1+1+1+1), or two of M5 (2+2), or one of M7 (4). One M8 body is already 5 and does not fit. E7 P1 + E3 = 10 Energy + 1 Power for four small bodies or one M7 — not for 'a garrison of four of any size'.
• THE MOONLIGHT AFFLICTION ROW OF ISSUE #97 IS AN ARITHMETIC SLIP AND THIS IS THE CORRECTION. It writes 'un solo cuerpo de M12: -10 -> -2'; 12 - 10 = 2. Rewritten: UNL-066 has no floor, so it maps M to M-10, and 143.2.b reads anything below 0 as 0. EVERY printed body of 10 Might or less lands at or below zero and costs Fox-Fire nothing at all — that covers VEN-091 Corrupted Dragon, OGN-142 Mountain Drake, OGN-158 Volibear Imposing and UNL-118 Elder Dragon. The two largest printed bodies in the pool are M12 (UNL-059 Master Yi Unstoppable, UNL-147 Baron Nashor) and land on 2, which still leaves room inside 4 for a 1 Might body beside them. E7 + E3 = 10 Energy and any single body in the game is gone.
• 143.2.b.1 IS THE PRICE OF THE TRICK: 'Although the unit's Might is treated as 0, it is not 0. Effects that calculate Might increases and decreases use the actual value of the unit's Might.' Undoing a -10 on an 8 Might body costs the opponent ten points of +Might, not two. The reduction is cheap to apply and expensive to answer.
• THE FRIGID TOUCH ROW IS CORRECT AS ISSUE #97 WROTE IT, AND 820 IS WHY IT IS NOT AN ENGINE. SFD-066 is E2 with '[Repeat] E2' and no floor. 820.1.b gives 'a second time', 820.1.c.3 caps it there ('Each Repeat Cost can be paid only a single time'), and 820.2.a lets the second execution pick a different unit ('Choices made for the additional execution do not have to be the same'). So 4 Energy is -2 on each of two bodies: a M3+M3 garrison becomes 1+1 = 2, a M2+M2 garrison becomes 0+0. Plus Fox-Fire at E3 the whole garrison is gone for 7 ENERGY. A third body needs a second Frigid Touch.
• THE [Hidden] DISCOUNT IS DEFENSIVE ONLY, AND THAT SPLITS THE CARD IN TWO. 811.1.b: you may pay 1 rainbow 'to hide this facedown at a battlefield you control'. 811.1.d.2 then confines a hidden spell's targets to that battlefield, and Fox-Fire names no other location so the escape clause never applies. So the 0 Energy Fox-Fire sweeps YOUR battlefield — the Nine-Tailed Fox legend's own scenario — while clearing THEIR garrison to walk in costs the full 3 Energy from hand. Only the second one leads to a Conquer.
• FOX-FIRE CHOOSES ITS VICTIMS, SO IT PAYS [Deflect] ONCE PER BODY. 355.11.a makes them a chosen group and 809.1.c charges 'for each time they choose'. This is the opposite of renekton-stare-down-evacuate, whose victims are selected by criteria (355.10.d) and cost nothing. And the card says 'units', not 'enemy units': your own bodies at that battlefield count toward the sum and can die, which is why the sweep and the walk-in are two steps and not one.
• THE CONQUER AFTERWARDS IS THE SAME CHAIN AS charm-evacuate-conquer AND renekton-stare-down-evacuate: 323.6 strips their Control at the Cleanup once the battlefield is empty, a ready body walks in (144.4.a, 144.2 / 420.3.a), 323.8 stages a Showdown and 323.9 stages no Combat, 323.12 opens it, 348.2.a and 348.2.a.1 give Control and a Conquer, 471.1 gives the point. No Attacker designation is ever claimed.

Steps

1. Choose which body is the problem. If it is one big body, Moonlight Affliction (E7, [Reaction], no floor) takes anything printed at 10 Might or less to zero or below, which 143.2.b reads as 0.
2. If it is two mid bodies, Frigid Touch with its Repeat paid (E2 + E2) gives -2 to each (820.2.a), taking a M3+M3 garrison to 1+1.
3. If it is a wide garrison of small bodies, Thousand-Tailed Watcher (E7 P1) maps each to max(1, M-3): four bodies of M4 or less become 1 each.
4. Add up the survivors at their CURRENT Might (710). If the total is 4 or less, play Fox-Fire from hand for 3 Energy — not from Hidden, which 811.1.d.2 would confine to your own battlefield — and choose the group (355.11.a). Add 1 rainbow per [Deflect] body chosen (809.1.c).
5. They all die at once. Do not include your own bodies: the card says 'units', not 'enemy units'.
6. The Cleanup strips their Control (323.6). Walk a ready body in (144.4.a) and take the Conquer through the Showdown (323.8 / 323.9 / 323.12 / 348.2.a / 348.2.a.1 / 471.1).

Per iteration

one Fox-Fire kills a garrison whose CURRENT Might sums to 4 or less, and an unfloored reduction contributes 0 to that sum instead of 1 — so the four-body ceiling of the floored version does not bind

How it ends

engine only — three Fox-Fires, each consumed, and every reducer is a card spent; nothing here scores

Sources

Published elsewhere

• Riftbound Core Rules, Last Updated 2026-07-16 (data/Riftbound-Core-Rules-2026-07-16.txt) 2026-07-16
• Lente de buff y Might — issue #97 (GitHub) 2026-09-06

Walked here, in this project

• Hand walk 2026-09-06 2026-09-06 record

Walked against Core Rules 2026-07-16

Match a deck list against the whole catalogue