Combo · ENGINE

820.4 - Marai Spire discounts a [Repeat] that Syndra GRANTED, and one Rebuke clears a garrison of two

3 cards · chaos · verified

Pieces

• Marai Spire ×1 SFD-211 · enabler

  While you control this battlefield, friendly [Repeat] costs cost 1 Energy less.

• Syndra, Transcendent ×1 UNL-146 · engine · chaos

  While I'm in a showdown, your spells have [Repeat] 2 Energy + 1 Chaos Power. (You may pay the additional cost to repeat the spell's effect.)

• Rebuke ×1 OGN-172 · payoff · chaos

  [Action] (Play on your turn or in showdowns.) Return a unit at a battlefield to its owner's hand.

Payoff

Deck

• Syndra and Rebuke are both mono-Chaos and Marai Spire is colorless (domains [] in data/cards.json), so the union is one domain and 103.1.b.3 admits the line under any legend carrying Chaos - fifteen legend pairs exist and five of them include Chaos, so no legend list narrows this entry.
• None of the three is Signature (signature false on all three in data/cards.json), so 103.2.d.2 forces no legend. None appears in data/legality.json in any format.

Prerequisites

• 820.4 WAS CITED BY NOTHING, AND IT IS THE PARAGRAPH THAT LETS THE SPIRE SEE A GRANTED [Repeat] AT ALL: 'Repeat, and whether or not a spell or ability has Repeat, is a characteristic of the spell or ability and may be checked or referenced by other Game Effects.' The Spire's text is exactly such a reference. Nothing in 820 or in 801.3.a distinguishes a granted instance from a printed one - 801.3.a is the bare permission ('Other effects may grant Keywords') and 801.3.a.2 and 801.3.a.3 govern only the DURATION of a grant - so the Spire discounts Syndra's instance as readily as a printed one.
• THE ARITHMETIC, IN FULL. Syndra's granted cost is :rb_energy_2::rb_rune_chaos:; the Spire takes it to :rb_energy_1::rb_rune_chaos:, and 356.6 ('Energy and Power costs can't be reduced below 0') floors only the Energy half and never touches the rune, so no further Spire could make it free. So the second Rebuke costs 1 Energy + 1 Chaos Power on top of Rebuke's printed E2 + 2 Chaos Power: THREE Energy and THREE Chaos Power in one turn for two bounces, with Syndra (E6 + 1 Chaos Power) already on the board from a previous turn, since 143.4 enters her exhausted and she cannot move the turn she is played.
• THE DELTA OVER THE ENTRY THAT ALREADY USES REBUKE. draven-rebuke-bloodless-combat clears a garrison of ONE with one Rebuke and wins the combat with no damage step. This clears TWO, and copies are not the alternative: 103.2.b caps Rebuke at three copies in the deck but only one can be cast per window that the Energy affords, and 820.3.a says outright 'Regardless of the number of times a spell or ability's instructions are executed with this keyword, it is only Played once' - so the pair of bounces is ONE play, which is also why a 'cards played this turn' count (SFD-012 Battering Ram, every [Legion] clause) still reads 1.
• THE LIMIT IS 820.2 AND IT IS THE HONEST HALF OF THE ENTRY: 'When a spell or ability's effect is performed an additional time with Repeat, choices must be made at the usual time during the Make Relevant Choices step of Playing a Card.' Both victims are named as you play Rebuke, before anything resolves. 820.2.a permits them to differ ('Choices made for the additional execution do not have to be the same as the choices made for the initial execution') but nothing lets you bounce one, watch the board, and then aim the second - and a defender that arrives AFTER you played Rebuke (464.2.c.3.a hands a designation at the following Cleanup) can never be a target of it. A garrison of three beats the line outright.
• WHY THE SPIRE IS NOT A DECKBUILDING FREEBIE, TWICE OVER. 485.4.a: 'Each player provides three (3) Battlefields, included in their deck during deck building. Only 1 will be used, chosen during setup', and 485.5 says the Duel 'randomly selects' it, so the Spire reaches the table one time in three; 103.4.c forbids three copies of one battlefield name. And 190.1 ('Control is established over Battlefields through the course of play') with 190.6.d ('If the battlefield has no Controller, "you" refers to no one, and all such instructions are ignored') means the discount is OFF until a body of yours stands there and 466.5 gives you Control - and it cannot be Syndra, who is away attacking. The line therefore needs a second body whose only job is to hold the Spire; it is not written into uses[] because the card is free choice, which is how ezreal-marai-spire-free-repeat handles the same requirement.
• 'IN A SHOWDOWN' IS READ NARROWLY, EXACTLY AS THE SISTER ENTRY READS IT. 740.2 defines 'alone', 'one on one' and 'in combat' (740.2.c) and says nothing about a unit being 'in a showdown'; 343.1 defines a Showdown STATE for the TURN, not for a unit. syndra-transcendent-existential-dread-three-executions takes the demanding reading - Syndra herself is at the battlefield where the Showdown is in progress - and this entry takes the same one, because a wider reading only adds windows and never removes one, so no reading needs to be filed either way.
• THE SECOND-ORDER CONSEQUENCE, STATED AND DELIBERATELY NOT PUT IN uses[]. 820.3: 'Multiple instances of Repeat can be paid for separately. The spell or ability's instructions will be executed an additional time on resolution for each instance of Repeat that is paid for.' Each instance is separately a friendly [Repeat] cost, so the Spire discounts BOTH - on a spell that prints its own [Repeat] :rb_energy_2: the printed instance falls to 0 and Syndra's falls to :rb_energy_1::rb_rune_chaos:, i.e. THREE executions for one Energy and one Chaos rune over the base cost. That board is syndra-transcendent-existential-dread-three-executions plus this battlefield, and adding UNL-134 here would make this entry a strict superset of that one, so it is a cross-reference and not a card set.
• WHAT THE TWO BOUNCES BUY. Rebuke is [Action], so 155 and 806.1.b let it be cast inside the opened Combat Showdown on any player's turn. 465.1 makes the damage tasks Outstanding only 'If both Attacking and Defending units remain at this battlefield' - empty the garrison and the damage step never happens; 466.3.a then makes you the winner ('the only Player that has units remaining at this battlefield during this step'), and 466.5.d makes establishing Control a Conquer 'if that player has not yet scored this Battlefield this turn'. Syndra takes no damage and the bounced bodies are in hand, not the trash, so no Deathknell and no trash payoff fires for the opponent.

Steps

1. Board state from a previous turn: Syndra, Transcendent on the board (E6 + 1 Chaos Power, and 143.4 entered her exhausted, so she could not move that turn), one other friendly body standing on Marai Spire so that 466.5 has given you Control of it and 190.6.d no longer blanks its 'you'. Rebuke in hand, 3 Energy and 3 Chaos Power available.
2. Main Phase: Standard-move Syndra to the enemy battlefield, paying her exhaust (144.2, 144.4). 190.3.a.1 applies Contested status and 464.2.c.1 makes you the Attacker.
3. 323.9 stages the Combat at the next Cleanup and 323.13 opens it; 464.2.f.1 leaves the State Open and 464.2.g lets players proceed on the Chain. Syndra is now standing at a battlefield where a Showdown is in progress, which is the narrow reading of her own condition.
4. Play Rebuke ([Action], so 155 and 806.1.b admit it here). During the Make Relevant Choices step, 820.2 requires every choice for BOTH executions now: name defender A and defender B, which 820.2.a permits to be different.
5. Pay Rebuke's printed E2 + 2 Chaos Power, then pay Syndra's granted Repeat cost as an Additional Cost during the steps of playing (820.1.c.1) - :rb_energy_2::rb_rune_chaos: reduced by the Spire to :rb_energy_1::rb_rune_chaos:, with 356.6 stopping the Energy at 0 and leaving the rune.
6. On resolution 820.1.d.1 executes the instruction twice: both named defenders go to their owner's hand.
7. 465.1 finds no Defending units remaining, so the Combat Damage tasks never become Outstanding. 466.3.a gives you the combat, 466.5 establishes Control and 466.5.d makes it a Conquer.

Per iteration

two enemy units returned to hand for one card and one play (820.3.a), where the same spell alone answers one

How it ends

engine - a garrison of two cleared with one spell and no damage step, for 3 Energy + 3 Chaos Power in the turn, on top of a 6 Energy + 1 Chaos Power body played a turn earlier and a second body parked on Marai Spire; 820.1.c.3 ('Each Repeat Cost can be paid only a single time') caps it at two executions per cast, so it never loops

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 2026-09-12, issue #191 - uncited Core Rules sub-rules 500-829 2026-09-12 record

Walked against Core Rules 2026-07-16

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