Combo · ENGINE

204.3.a against 204.3.b: WHERE a 'pay X to do Y' sits inside a trigger decides finalization or resolution - so the 2 XP Insightful Investigator asks for CAN be funded by triggers of the same event, and Riot names the card

6 cards · chaos + body · verified

Pieces

• Insightful Investigator ×3 UNL-135 · payoff · chaos

  When you play me, choose an opponent. They reveal their hand. You may pay 2 XP to choose a card from their hand. If you do, they discard that card and draw 1.

• Blood Rose ×3 UNL-109 · resource · body

  When you play a unit, you may pay 1 Energy to gain 1 XP. Spend 3 XP, Exhaust: Ready a unit.

Payoff

Deck

• Insightful Investigator is mono-Chaos and Blood Rose is mono-Body, so 103.1.b.2 needs a legend covering both. Measured over data/cards.json on 2026-09-12 there are exactly THREE Body/Chaos legend names: Bounty Hunter, Battle Mistress and Voidreaver.
• Neither is a Signature card (checked against data/cards.json), and neither appears in data/legality.json in any format - checked 2026-09-12, and data/legality.json's only non-banned row is the Wuju Bladesman starter legend, restricted in 2v2, which is Calm/Body and not a legend this line can use.
• Blood Rose has to be on the board before the Investigator is played, because its trigger watches that play. It is E1 and a gear, so 143.4 never exhausts it and it can be cast the turn before for one Energy.
• The opponent has to hold a card. The reveal happens whether or not you pay, so the information is free and only the removal costs XP.

Prerequisites

• THE RULE, AND IT IS A REFINEMENT TO A STANDING CLAIM OF THIS PROJECT, NOT A NEW ONE. This catalogue says repeatedly that a cost written at the start of a Triggered Ability's effect is the ability's BASE cost, paid at finalization - true, and 204.3.a is the cleanest source, with its own worked example: 'Overzealous Fan is a unit that reads “When I defend, you may kill me to move an attacking unit to its base.” In order to finalize the ability to the chain, its controller must kill Overzealous Fan.' What the project has been missing is the OTHER half, 204.3.b: 'When Costs within Instructions appear in spells, activated abilities, or in later parts of triggered abilities, the cost must be paid to get the effect during resolution of the spell or ability.' 204.3.a is cited 32 times through 204.3; 204.3.b's 'later parts' clause has never been used. The test is POSITION INSIDE THE SENTENCE, exactly as 383.2.a.1's word-order test is for a condition.
• AND RIOT SPELLS OUT THE CONSEQUENCE ON THIS CARD. 204.3.b's third worked example: 'Insightful Investigator is a unit that reads “When you play me, choose an opponent. They reveal their hand. You may pay 2 XP to choose a card from their hand. If you do, they discard that card and draw 1.” As the ability resolves, its controller may pay 2 XP as a cost, and chooses a card from that player’s hand as the effect.' So the XP does not have to exist when the trigger is placed - only when it resolves.
• WHICH IS WHY THE SAME EVENT CAN PAY FOR IT, AND THAT IS THE CONSTRUCTIVE HALF. This project records three times, from three different rules, that a resource produced by another trigger of the same event can NEVER fund a 383.3.b / 204.3.a base cost, because 383.3.b.1 demands payment at finalization and 312.2.c hands out no priority in between. 204.3.b is the exception that proves the shape: with three Blood Rose on the board, playing the Investigator puts FOUR triggers on the Chain at once (383.3.d lets you order them). Place the Investigator's FIRST so 340.1 resolves it LAST; the three Blood Rose triggers resolve first for 1 Energy each, and the Investigator then pays 2 of the 3 XP they just produced. Nothing had to be banked.
• THE ARITHMETIC, WITH THE QUANTITIES DECLARED. Three Blood Rose at E1 each is a one-off 3 Energy of setup. The turn you play Insightful Investigator: E3 for the body, 3 Energy into the three Blood Rose triggers, 2 XP spent, 1 XP left over and a 3 Might body on the board. Six Energy strips their chosen card. It is SURGICAL removal and not card advantage - 'they discard that card and draw 1' leaves their hand the same size - so this takes the one card that beats you, and the reveal tells you which it is before you decide to pay.
• THE BLOOD ROSE HALF IS A FAUCET BECAUSE THE COST HAS NO EXHAUST. The XP clause is 'When you play a unit, you may pay 1 Energy to gain 1 XP' - no exhaust anywhere in it - so three copies all fire on one unit play, and every unit you play afterwards is another 1 XP per copy per Energy. The exhaust is on the SECOND ability ('Spend 3 XP, exhaust: Ready a unit'), which 415.3.a refunds only at your own Awakening, so the ready is once a turn and the XP is not.
• THE ANTI-SYNERGY, AND IT IS THE ONE THAT CATCHES XP DECKS. 730.2: 'To Spend XP, reduce the value of XP marked on the Player spending it.' And 824.1.d: 'The Dependent Ability will be Inactive as soon as the controlling player has less than [N] XP.' So paying the Investigator's 2 XP switches off every [Level N] rung you were standing on. This line wants a faucet and NO [Level] statics - it is a SINK deck, and the Blood Rose entries that pair it with Wuju Master's rungs are built on the opposite premise. See wuju-master-blood-rose-level and gardens-becoming-wuju-xp-faucet, which want the XP held; this entry wants it spent.
• WHAT THIS PAIRING ADDS OVER THE ONE ALREADY IN THE CATALOGUE. mindsplitter-insightful-investigator-hand-attack runs the Investigator with OGN-192 Mindsplitter for a second look at the same hand; it does not touch where the 2 XP comes from, which is the only question 204.3.b answers. The two compose - Mindsplitter takes a card without XP, the Investigator takes one with it - and neither is a prerequisite of the other.

Steps

1. Play UNL-109 Blood Rose for 1 Energy on an earlier turn; 103.2.b allows three and each is its own trigger source.
2. On the turn you want their card, play UNL-135 Insightful Investigator for 3 Energy.
3. That one play meets four Trigger Conditions at once: each Blood Rose's 'When you play a unit' and the Investigator's own 'When you play me'. 383.3.d gives you the order.
4. Place the Investigator's trigger FIRST and the three Blood Rose triggers after it, so 340.1 ('The newest Finalized Chain Item resolves') runs the Blood Rose triggers first.
5. Each Blood Rose trigger asks for 1 Energy at FINALIZATION - its cost is the first part of its effect, so 204.3.a and 383.3.b.1 apply to it. Pay all three: 3 Energy, 3 XP.
6. The Investigator's trigger now resolves. Choose the opponent; they reveal their hand; that much is free.
7. 204.3.b: the 2 XP is a Cost within an Instruction in a LATER part of the trigger, so it is paid HERE, at resolution, out of the XP the earlier triggers just produced. Riot's worked example for this paragraph is this card.
8. Choose a card from their hand. They discard it and draw 1. Their hand size is unchanged and the card you feared is in the trash.
9. You are left with 1 XP and a 3 Might body, for 6 Energy in total. Spend no more XP if you are running any [Level] rung - 824.1.d switches it off the instant you drop below the threshold.
10. Three copies of each (103.2.b). Nothing here loops inside a turn and nothing here scores.

Per iteration

one named card taken out of the opponent's hand for 6 Energy and 2 XP, with the 2 XP funded by triggers of the same event - which a base cost could not be

How it ends

engine only - nothing here scores. One Investigator play is one strip; the Blood Rose faucet pays 1 XP per copy per unit played and its ready ability is capped at once a turn by its own exhaust (415.3.a)

Sources

Published elsewhere

• Riftbound Core Rules, Last Updated 2026-07-16 (data/Riftbound-Core-Rules-2026-07-16.txt), 204.3.a and its worked example 2026-07-16
• Riftbound Core Rules, Last Updated 2026-07-16 (data/Riftbound-Core-Rules-2026-07-16.txt), 204.3.b 2026-07-16
• Riftbound Core Rules, Last Updated 2026-07-16 (data/Riftbound-Core-Rules-2026-07-16.txt), 204.3.b third worked example 2026-07-16
• Riftbound Core Rules, Last Updated 2026-07-16 (data/Riftbound-Core-Rules-2026-07-16.txt), 730.2 and 824.1.d 2026-07-16
• Card text, data/corpus_flat.txt (built from Riot's gallery content API by scripts/build-cards.mjs) 2026-09-12

Walked here, in this project

• Hand walk 2026-09-12 (docs/phase0/walks/2026-09-07-uncited-rules-blocks.md), batch 17 2026-09-12 record

Walked against Core Rules 2026-07-16

Match a deck list against the whole catalogue