Combo · ENGINE

The mutual-damage family's ceiling is whatever you pumped first - and Onslaught pays that twice from one card

6 cards · body · verified

Pieces

• Gentlemen's Duel ×3 OGS-008 · payoff · body

  [Action] (Play on your turn or in showdowns.) Give a friendly unit +3 Might this turn. Then choose an enemy unit. They deal damage equal to their Mights to each other.

• Onslaught ×3 VEN-081 · engine · body

  Give a unit +6 Might this turn. [Flow] 4 Energy (You may play this from your trash for its Flow cost. Then banish it.)

Payoff

Deck

• All cards are mono-Body, so 103.1.b.3 admits any legend with Body in its pair: SFD-203/SFD-250 Battle Mistress, OGN-257/OGN-304 Blind Monk, OGN-267/OGN-309 Bounty Hunter, VEN-141/VEN-190 Butcher of the Sands, VEN-149/VEN-194 Defender of Tomorrow, SFD-205/SFD-251 Grand Duelist, SFD-193/SFD-245 Grandmaster at Arms, UNL-203/UNL-237 Keeper of the Hammer, VEN-153/VEN-196 Matriarch of War, OGS-023 Might of Demacia - Starter, UNL-183/UNL-227 Pridestalker, SFD-183/SFD-241 Purifier, OGN-249/OGN-300 Relentless Storm, OGN-269/OGN-310 The Boss, UNL-201/UNL-236 Voidreaver, OGS-019 Wuju Bladesman - Starter, UNL-191/UNL-231 Wuju Master.
• Neither card is banned or restricted in either format, and neither is a Signature card.
• A friendly unit worth pumping and an enemy unit worth killing. Both halves choose, so a [Deflect] body taxes each of them separately (809.1.c). CORRECTED 2026-10-18 (#405, from the run play docs/plays/2026-10-18-onslaught-and-the-duel-beat-an-ambushed-vilemaw-only-together-and-the-second-spell-is-what-crumbling-sands-counters.md): 809.1.c taxes only an opponent's spells: "It is functionally short for "Spells and abilities an opponent controls that target [me/this] cost an amount of Power equal to [Deflect Value] more to play as an additional cost for each time they choose [me/this]."" The friendly half chooses your own unit, and Onslaught chooses it too, so the pair pays at most one tax: the enemy target's [Deflect] value.

Run play

• Onslaught and the Duel beat an ambushed Vilemaw only together, and the second spell is what Crumbling Sands counters

Prerequisites

• WHY THE ORDER INSIDE ONE CARD MATTERS. Gentlemen's Duel reads 'Give a friendly unit +3 :rb_might: this turn. Then choose an enemy unit.' The pump resolves before the exchange, so the +3 is inside the fight. Every other member of the family fights at printed Might unless a separate card was spent first, which is what makes this one the natural home for a stacked pump. CORRECTED 2026-10-18 (#405, from the run play docs/plays/2026-10-18-onslaught-and-the-duel-beat-an-ambushed-vilemaw-only-together-and-the-second-spell-is-what-crumbling-sands-counters.md): except VEN-083 Rampage with its optional Body Power paid, which gives the friendly unit +2 this turn and then makes the two units deal damage to each other, from one card. The Duel is still the only one whose pump is unconditional, and it is bigger (+3 against +2).
• 417.6.b.3 IS WHAT THE WHOLE FAMILY STANDS ON, AND ITS WORKED EXAMPLE IS CHALLENGE. 'When a spell or ability specifies a Unit as the source of the Damage for the Deal action, it is not in addition to the spell or ability that instructed it.' So this is UNIT damage: 815.1.b and 815.1.c.2 scope [Tank] to 'the Combat Damage step' and never touch it, and a blanket spell-and-ability fog leaves it working. The cost is 417.6.b.4 - the controller of the ENEMY unit is responsible for their half, and their 'when you deal damage' triggers fire.
• AND THE CEILING IS ARITHMETIC, NOT A RULE. 143.2.a kills a unit when marked damage reaches its Might, and there is no minimum-lethal cap here (465.2.c.4 is a combat-assignment rule), so the exchange simply compares two numbers. A Might-6 body carrying Onslaught's +6 and the Duel's own +3 fights at 15 - above every printed Might in the pool - while taking back only the target's Might. Without a pump the same 6 Energy + 1 Power kills a 9 at best and dies to anything above 6.
• [FLOW] IS SIX PLAYS A GAME AND NOT AN ENGINE. 829.1.b: 'You may play this from your trash for its flow cost. Then banish it', and 829.1.b.1 makes that banish a delayed replacement. With 103.2.b's three copies that is six Onslaughts in a game and no more, since 108.6.c keeps a banished card out of play. The second play costs the same 4 Energy as the first, which is unusually flat for the keyword. CORRECTED 2026-10-18 (#405, from the run play docs/plays/2026-10-18-onslaught-and-the-duel-beat-an-ambushed-vilemaw-only-together-and-the-second-spell-is-what-crumbling-sands-counters.md): not unusual. Fifteen cards print their own [Flow] cost, and five of them repeat their base cost exactly: VEN-012 Perfect Execution, VEN-049 Dredge Up, VEN-081 Onslaught, VEN-100 Up from the Deep, VEN-116 Dragon Form.
• THE TIMING SPLIT INSIDE THE PAIR. Gentlemen's Duel is [Action] (806.1.c.1: 'This can be played during showdowns on any player's turn'), so it can be held until a combat has opened; Onslaught carries no keyword at all, so 155 - 'A spell can be played during an Open State outside of Showdowns on its controller's turn' - confines it to your own Main Phase. The pump has to be committed BEFORE the fight, which is the honest cost of the biggest number in the domain. CORRECTED 2026-10-18 (#405, from the run play docs/plays/2026-10-18-onslaught-and-the-duel-beat-an-ambushed-vilemaw-only-together-and-the-second-spell-is-what-crumbling-sands-counters.md): Onslaught carries [Flow]. It has no timing keyword, and that is what 155 reads. And the biggest number in the domain is OGN-154 Primal Strength (+7, E4 + 1 Body Power), which is [Action] (806.1.b: "Action grants the corresponding card or effect permission to be played or activated during Showdowns, even when it is not the Controlling player's turn."). So the honest cost is Onslaught's, not the domain's: Onslaught is committed before the attack, before an [Ambush] defender is known, and Primal Strength can wait until the combat shows one, for one more recycled Body rune. It has no [Flow].
• THE LEDGER, WITH THE QUANTITIES DECLARED. Onslaught 4 Energy for +6; Gentlemen's Duel 6 Energy + 1 Power for +3 and the exchange. Ten Energy and one Power removes any single unit in the pool and leaves your body alive unless the target's Might exceeds the pumped total. Six Onslaughts and three Duels a game. CORRECTED 2026-10-18 (#405, from the run play docs/plays/2026-10-18-onslaught-and-the-duel-beat-an-ambushed-vilemaw-only-together-and-the-second-spell-is-what-crumbling-sands-counters.md): not any unit. These are examples, not a census: SFD-105 Ruin Runner ("I can't be chosen by enemy spells and abilities.") and UNL-147 Baron Nashor, one of the pool's two printed 12s, cannot be chosen at all; VEN-038 Akali, Silent cannot be chosen except in combat ("I can't be chosen by enemy spells and abilities unless I'm in combat."); UNL-059 Master Yi, Unstoppable not once he reaches [Level 16]; UNL-057 Alpha Wildclaw protects their smaller units at its battlefield ("Your units here with less Might than me can't be chosen by enemy spells and abilities."); and VEN-031 Twilight Shroud ("Give a friendly unit +1 :rb_might: this turn. It can't be chosen by enemy spells and abilities this turn.") protects one unit. Twilight Shroud has no timing keyword and its protection lasts "this turn", so it stops only a Duel played on their turn, during a combat (806.1.b). A [Deflect 2] target (VEN-046 Nasus, Ascended, OGN-041 Volibear, Furious, SFD-120 Sivir, Ambitious, SFD-085 Ornn, Forge God, VEN-122 Solari Sunhawk Empowered, VEN-088 Jayce, Hammer in Hand in that mode) makes it ten Energy and three Power, and VEN-134 Kayle, Justified Empowered three times has [Deflect 3], so four Power. Ten runes is T5 at the earliest from either seat, since each player channels two a turn (315.3.b: "1. The Turn Player channels 2 runes from their Rune Deck.") and the second player one more on their first turn (485.7: "First Turn Process: The player going second channels an extra Rune from their Rune Deck during their first Channel Phase of the game."). Going first it is the whole T5, and going second ten of eleven.
• WHAT IT IS NOT. Nothing here scores; 469 defines Scoring as Conquer or Hold. And 417.6.c keeps every point of the exchange out of the excess-damage family, so none of this feeds a Tryndamere.
• NO ANSWER WAS NAMED - ADDED 2026-10-18 (#405, from the run play docs/plays/2026-10-18-onslaught-and-the-duel-beat-an-ambushed-vilemaw-only-together-and-the-second-spell-is-what-crumbling-sands-counters.md). The pair is two spells in one turn, and that is what the cheapest answer reads. VEN-039 Crumbling Sands (Calm, E1 + 1 Calm Power: "[Reaction] (Play any time, even before spells and abilities resolve.) Counter a spell if an opponent has played another spell this turn.") counters the Duel once Onslaught has been played; the Duel alone is one spell, and its condition is false. OGN-045 Defy (Calm, E1 + 1 Calm Power: "[Reaction] (Play any time, even before spells and abilities resolve.) Counter a spell that costs no more than :rb_energy_4: and no more than :rb_rune_rainbow:.") counters Onslaught (E4, no Power) in your Main Phase, and cannot reach the Duel (E6). 425.1.a: "A card or ability that is Countered does nothing and is cleared from the chain." In the play's walk either one fits with an ambushed UNL-060 Vilemaw (Calm, E8 + 2 Calm Power) in nine runes, and either keeps the battlefield.

Bodies no card supplies

In your Main Phase, play Onslaught (4 Energy) on the body you intend to fight with: +6 Might this turn

Steps

1. In your Main Phase, play Onslaught (4 Energy) on the body you intend to fight with: +6 Might this turn. 155 is why this cannot wait for a showdown.
2. Play Gentlemen's Duel (6 Energy + 1 Power) under its [Action] permission. Its own +3 resolves first, so the body fights at printed Might + 9.
3. Choose the enemy unit. 417.6.b.3 makes both halves UNIT damage, so a [Tank] in that garrison orders nothing and a spell-damage fog does not stop it.
4. Both bodies take damage equal to the other's Might; 143.2.a kills whichever reaches its own Might. Expect the opponent's 'when you deal damage' triggers to fire for their half (417.6.b.4).
5. Later in the game, replay Onslaught from your trash for its [Flow] cost of 4 Energy; 829.1.b banishes it afterwards, so each copy is worth exactly two plays.

Per iteration

one enemy unit of up to printed Might + 9 removed, for 10 Energy and 1 Power, with the friendly body surviving anything smaller

How it ends

engine only - three Duels and six Onslaught plays a game (103.2.b with [Flow]), and the exchange is mutual so a bad choice loses the friendly body; nothing here scores and 417.6.c keeps it out of the excess-damage family

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-body.md, batch 3) 2026-09-07 record
• Run play 2026-10-18, issue #401 2026-10-18 record

Walked against Core Rules 2026-07-16

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