Combo · ENGINE

Shard of Undoing fed by Sprite Fountain — one forced enemy kill per turn, two turns per Fountain

4 cards · order + mind · verified

Pieces

• Shard of Undoing ×1 UNL-174 · payoff · order

  The first time a friendly unit dies during your Beginning Phase each turn, each opponent must kill one of their units.

• Sprite Fountain ×3 UNL-078 · engine · mind

  [Temporary] (Kill this at the start of its controller's Beginning Phase, before scoring.) When you play this, play a ready 3 Might Sprite unit token with [Temporary] to your base. [Deathknell][>] Repeat this gear's play effect. (When this dies, get the effect.)

Payoff

Deck

• Legend domains cover Mind and Order. Sprite Fountain is mono-Mind and Shard of Undoing is mono-Order, so 103.1.b.3 (single domain) admits each on its own; the deck still needs a legend holding both, and the pool has exactly four — OGN-265 Herald of the Arcane (Viktor), OGS-021 Lady of Luminosity - Starter (Lux), SFD-201 Chem-Baroness (Renata Glasc), UNL-199 Deceiver (LeBlanc). None of the six cards involved is banned or restricted in either format.

Prerequisites

• THE CEILING IS ONE FORCED KILL PER TURN, NOT ONE PER SPRITE. 383.3.e.1: 'Such a Triggered Ability will only be performed the specified number of times each turn. If its trigger condition would be fulfilled and it has already been performed that many times, it does not trigger.' The Shard reads 'the first time ... each turn', which 383.1 identifies as the [Nth]-time trigger form (383.1.b's worked example is Wraith of Echoes, 'The first time another friendly unit dies each turn, draw 1'). So three Fountains played on the SAME turn buy two forced kills, not six: three Sprites die in your next Beginning Phase and 383.3.e.1 discards two of those deaths, then three more die the turn after and it discards two again.
• THE THREE COPIES MUST BE PLAYED ON A TWO-TURN CADENCE. Each Fountain supplies exactly two consecutive turns of Beginning-Phase deaths: the Sprite from its play effect dies on turn T+1, the Sprite from its Deathknell dies on T+2, and then the gear is in the trash. Played on T, T+2 and T+4 the three copies cover T+1 through T+6 with one death each — six forced kills. Played on T, T+1, T+2 they overlap and yield four. Played together they yield two. The '6' is a schedule you play to, not a quantity you hold.
• THE SECOND SPRITE SURVIVES THE TURN IT IS BORN, AND THAT IS THE WHOLE ENGINE. 816.1.c makes the Trigger Condition of [Temporary] 'the controller of the permanent's Beginning Phase starting'; 383.2.c.1 triggers an ability only if its object 'enters that zone at the same time that its Trigger's condition is met'. The Deathknell's Sprite enters during the resolution of a trigger, strictly after that start, so its own [Temporary] is never evaluated that turn. Same window gutter-palace runs on (issue #62).
• THE DEATHKNELL ON A GEAR IS 808.1.a + 808.1.d.2, NOT 428.1.a.1.b. 808.1.a: '[Deathknell] is present on Permanents.' 808.1.d.2: 'The trigger will be added to the chain as a Pending Item before the card with an ability that triggers on its own death is moved to the trash due to a Kill instruction or a Cleanup.' 808.1.d.3 preserves what the trigger needs to execute from the trash. 428.1.a.1.b says 'a unit' and does not reach gear. Nothing replaces the Fountain's death, so 808.1.d.1 never removes the trigger.
• THE TWO KILLS ARE SEQUENTIAL, NOT SIMULTANEOUS, SO 383.2.c.2 NEVER BITES. Both [Temporary] abilities trigger on the same condition and you order them (383.3.d), but they are two chain items and 340.1 resolves them one at a time. The ordering is therefore free: either way one Sprite dies and one Deathknell fires. (383.2.c.2 — the Viktor, Leader case where a trigger is lost because its source leaves at the same time — cannot apply to the Shard, which carries no [Temporary] and never leaves.)
• THE REMOVAL IS FORCED BUT NEVER AIMED, AND [Deflect] NEVER TAXES IT. 355.10.e: 'It is part of a set of objects chosen in whole or in part by other players. e.g., "Each player kills a unit they control" does not target.' 355.10.f: 'It is identified in an instruction that a player "must" complete.' So the Shard targets nothing and the OPPONENT picks which of their units dies — a Recruit or a Bird token is a unit (185.2.d), so a wide board pays almost nothing. Against two premium bodies it is real. The flip side of not targeting: 809.1.c/809.1.d charge Deflect only on spells and abilities that target or choose the Deflect body, so a Bird token's Deflect is no shield here.
• A WHIFF STILL BURNS THE TURN'S TRIGGER. With no enemy units, 055 ignores the instruction ('do as much as you can, ignoring impossible instructions') but 383.3.e.1 counts the performance. Academic — an opponent with no units has nothing to lose either way.
• IT DOES NOT CONTRADICT sprite-fountain-malzahar-jayce, IT INVERTS IT. That entry's REFUTE note killed both of its sinks with '[Temporary] Sprites never see a Hold or a Main Phase start' (816.1.b, 315.2.b). This entry buys the death itself, which is the one thing that sentence guarantees.

Steps

1. Land Shard of Undoing (6 Energy, no Power). It is gear with no location clause, so 355.2.a puts it at your base and it stays there.
2. Turn T, Main Phase: play Sprite Fountain (2 Energy + 1 Mind Power). Its play effect makes a ready 3 Might Sprite with [Temporary] at your base.
3. Turn T+1, Beginning Step (315.2.a.1, after Awaken 315.1.b): both [Temporary] abilities trigger on the same condition (816.1.c) and you order them (383.3.d); 340.1 resolves them one at a time. The Sprite's kill (816.1.b) is a friendly unit death during your Beginning Phase — the Shard triggers and each opponent must kill one of their units, of their own choosing (355.10.e/f).
4. The Fountain's kill puts its [Deathknell] on the chain before the gear reaches the trash (808.1.a, 808.1.d.2, 808.1.d.3). It repeats the play effect: a second ready 3 Might Sprite with [Temporary]. That Sprite entered after the Beginning Phase started, so 383.2.c.1 spares it this turn.
5. Turn T+2: the second Sprite's [Temporary] kills it, the Shard's per-turn counter has reset (383.3.e.1), and the opponent kills a second unit. This Fountain is spent — there is no third Sprite.
6. Play the second Fountain on turn T+2 and the third on T+4 so no two Sprite deaths land in the same Beginning Phase. Six turns of forced removal for 12 Energy and 3 Mind Power total.

Per iteration

one enemy unit killed per turn of yours, chosen by the opponent. Each Sprite Fountain funds exactly two such turns (its play-effect Sprite and its Deathknell Sprite); no Energy, Power, card or draw is spent at trigger time.

How it ends

engine only — one forced enemy kill in each of your Beginning Phases, capped at one per turn by 383.3.e.1. Three Fountains played on a two-turn cadence (T, T+2, T+4) cover six consecutive turns for 12 Energy + 3 Mind Power; played all at once they cover two. 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
• Riot gallery card text (data/corpus_flat.txt, errata applied) 2026-09-06
• Gear-without-Equipment lens — issue #107 (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

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