Combo · ENGINE

437.3 - a Prevent Value is a POOL that is spent down and survives, so Ki Barrier's seven covers several small hits, and on a [Tank] it is a toll the whole garrison hides behind

6 cards · order · verified

Pieces

• Ki Barrier ×3 VEN-126 · payoff · order

  [Reaction] (Play any time, even before spells and abilities resolve.) Choose a unit. Prevent the next 7 damage that would be dealt to it this turn. (Opponents can assign it extra combat damage to kill it.)

• Shen, Kinkou ×3 OGN-241 · enabler · order

  [Reaction] (Play any time, even before spells and abilities resolve, including to a battlefield you control.) [Shield 2] (+2 Might while I'm a defender.) [Tank] (I must be assigned combat damage first.)

Payoff

Deck

• Both cards are mono-Order, so 103.1.b.1 is satisfied by any legend carrying Order. The census run against data/cards.json on 2026-09-09 gives seventeen names; among them Hand of Noxus (OGN-253), Radiant Dawn (OGN-261), The Boss (OGN-269), Void Burrower (SFD-187), Chem-Baroness (SFD-201) and Matriarch of War (VEN-153).
• Neither card is Signature (data/cards.json, signature=false on both) and neither appears in data/legality.json in either format - checked 2026-09-09.
• Both are [Reaction], so 813.1.c.1 lets the whole line be assembled on the opponent's turn; nothing here has to be committed in your own Main Phase.

Prerequisites

• 437.3 WAS UNCITED AND IT REVERSES THE OBVIOUS READING OF KI BARRIER. The natural reading is that a Prevent is a one-shot spent by whatever it meets first. It is not. 437.2: 'When damage is Prevented, it is replaced with an event where it deals that much damage reduced by the Prevent Value tracked on the Unit specifically.' 437.3: 'When damage is dealt this way, reduce the Prevent Value being tracked on the Unit affected by the Prevent action by the prevented amount.' 437.3.b: 'The reduced value is the newly tracked Prevent Value.' 437.3.a: 'If the Prevent Value is 0 or less, then Prevent is no longer being tracked on the Unit in question, and the effect expires.' So a Prevent 7 that eats a Deal 2 is a Prevent 5 and keeps working - it is a POOL for the turn, not a single answer.
• WHICH MAKES THE POOL'S TWO BOUNDED PREVENTS OPPOSITE TOOLS, AND ONE OF THEM IS NOT A FREE SWAP. 437.1.b.2: 'Prevent will always apply to the next damage that would be dealt to a unit affected by the Prevent action.' SFD-194 Counter Strike says 'The next time that unit would be dealt damage this turn, prevent it' - ONE instance of any size, so it is the answer to OGS-022 Final Spark, the pool's single largest Deal at 8, and is spent entirely by a 1-damage ping. Ki Barrier is the answer to a spell that performs several Deal actions, and OGN-248 Icathian Rain is the measured case: it prints 'Deal 2 to a unit.' six times, so aimed at one body Ki Barrier absorbs 2, 2, 2 and 1 of the fourth - seven of twelve - where Counter Strike absorbs two. Counter Strike is also a Signature card tagged Jax (data/cards.json, signature=true), so 103.2.d.2 forces a Jax legend on any list that runs it; Ki Barrier is not Signature and costs a list nothing.
• 437.3.c IS WHY THE OTHER TWO PREVENTS ARE DIFFERENT IN KIND: 'If the Prevent Value is "All" then it remains "All."' OGN-145 Unyielding Spirit and VEN-025 Esteemed Hierophant are unbounded and are never spent down; the whole 437.3 arithmetic is visible only on a numbered Prevent, and the pool prints exactly one (swept over data/corpus_flat.txt on 2026-09-09: the four Prevent rows are OGN-145, SFD-194, VEN-025 and VEN-126).
• ON A [TANK] THE SEVEN COVERS EVERYTHING, NOT ONE BODY. 437.5.a: 'Damage can be assigned to a Unit up to a value that would be Lethal considering the Prevent Value of all Prevent Actions on a Unit, following the normal rules for damage assignment.' Shen defending is Might 3 plus [Shield 2] (814.1.c is conditional on the Defender designation), so lethal is 5; with Ki Barrier it is 12. 815.1.c.2: 'Units without Tank are invalid assignments until all units with Tank have lethal damage assigned to them.' Until twelve damage is assigned to Shen, no other body of yours is a legal assignment at all.
• 465.2.c.7 WAS ALSO UNCITED, AND IT IS WHY A SECOND SHEN IS NOT A SPARE. 815.2 - 'Multiple instances of Tank are redundant' - is already cited by the catalogue and is about a second GRANT on one body. A second Tank BODY is a different thing, and 465.2.c.7 works it: 'If multiple Units have abilities or effects that require a player to assign them damage with the same priority, that player may assign damage to those units in any order.' Its EXAMPLE is this exact board: 'A player is assigning damage to the following units: two units with Tank ("I must be assigned combat damage first.") and one unit with no abilities. That player chooses one of the units with Tank and assigns combat damage to it. Then they must assign any remaining damage first to the other unit with Tank, then to the unit with no abilities.' So two Shens are a toll of 5 + 5, and with Ki Barrier on one of them 12 + 5 = 17 before any other body of yours is a legal assignment. The attacker chooses the ORDER and never the target.
• THE SHORTFALL IS THAT IT IS ONE TARGET. Ki Barrier says 'Choose a unit', so a sweeper that deals to every body at a battlefield spends the seven on one of them and kills the rest; and 437.4 ('Damage dealt to a Unit that has that all of that damage Prevented is not considered to have been dealt to it at all') is a benefit only on the body that was chosen. Nothing here scores - the class is ENGINE because 466.5 gives Control only to a player who did not already have it, and this line is played by the side that already does.
• 437.1.a.1 IS THE HALF ALREADY WALKED, AND IT COSTS THE POOL: 'Prevent includes any applied Bonus Damage when determining the total damage being prevented.' The catalogued entry void-gate-ki-barrier-prevent-counts-bonus-damage reads that from 715.4.a's side on OGN-296 Void Gate; carried into this entry it means every Deal action into a Bonus Damage board spends one more point of the seven than its printed number suggests.
• 437.2.a IS THE FLOOR: 'The damage being dealt as a result of Preventing can never be less than 0, but can be 0. This is equivalent to not dealing damage.' Read with 417.1.e ('Valid Damage is a positive integer amount, greater than or equal to 1 Damage') and 417.1.e.1 ('Only Valid Damage is Dealt'), a fully absorbed Deal generates no damage event at all, so no 'when I take damage' trigger of theirs fires off it either.

Steps

1. Hold Shen, Kinkou and Ki Barrier. Both are [Reaction], so 813.1.c.1 admits them in any Closed State on any player's turn.
2. When the opponent's attack is declared, play Shen to the contested battlefield - his own parenthetical grants 'including to a battlefield you control'. 319.6 with 323.2.a and 464.2.c.3.a give a body that becomes present mid-combat its designation at the next Cleanup, before 465.2 resolves.
3. Play Ki Barrier on Shen for 2 Energy + 1 Order Power. Prevent Value 7 is now tracked on him.
4. 465.2.c has each side assign its summed Might. 815.1.c.2 makes every other body of yours an invalid assignment until Shen has lethal, and 437.5.a sets lethal at Might 3 + [Shield 2] + Prevent 7 = 12.
5. If instead they answer with spells, 437.3 spends the pool down instance by instance rather than all at once: a Deal 2 leaves Prevent 5, a second leaves Prevent 3, and 437.3.a only expires it at 0 or less.
6. At your Awakening, 415.3.a readies Shen; the Prevent is gone, because Ki Barrier says 'this turn'.

Per iteration

one turn in which the chosen body absorbs 7 damage in total, in any number of instalments, and [Tank] makes it the only legal assignment

How it ends

engine - 5 Energy + 2 Order Power, all at [Reaction] speed, for a defender that costs 12 assigned damage to kill and that every other body of yours hides behind; a second Shen raises the toll to 17 under 465.2.c.7, because a second Tank BODY is not redundant even though a second Tank GRANT is (815.2). Alternatively seven points of spell damage absorbed across as many separate Deal actions as the turn contains; no point is scored

Sources

Published elsewhere

• Riftbound Core Rules, Last Updated 2026-07-16 (data/Riftbound-Core-Rules-2026-07-16.txt) 2026-07-16

Walked here, in this project

• Hand walk 2026-09-09, issue #187 - uncited Core Rules sub-rules 300-499 2026-09-09 record

Walked against Core Rules 2026-07-16

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