Combo · ENGINE
One 4-Energy spell turns on both halves of the 'if you spent' family — a free [Predict] and a 4-Energy body for one Power
Pieces
- Forgotten Library ×1
UNL-211 · battlefield
While you control this battlefield, when you play a spell, if you spent 4 Energy or more, [Predict]. (Look at the top card of your Main Deck. You may recycle it.)
- Jhin, Meticulous Killer ×3
UNL-089 · payoff · mind
[Vision] (When you play me, look at the top card of your Main Deck. You may recycle it.) If you've spent 4 Energy or more to play a spell this turn, you may play me for 1 Mind Power.
Payoff
Deck
- Jhin, Meticulous Killer is mono-Mind and Forgotten Library is Colorless, so 103.1.b.3 admits any legend with Mind in its pair: UNL-189/UNL-230 Bashful Bloom, SFD-201/SFD-249 Chem-Baroness, VEN-145/VEN-192 Curator of the Sands, OGN-247/OGN-299 Daughter of the Void, UNL-199/UNL-235 Deceiver, VEN-149/VEN-194 Defender of Tomorrow, SFD-189/SFD-244 Fire Below the Mountain, OGN-265/OGN-308 Herald of the Arcane, OGS-021 Lady of Luminosity, SFD-181/SFD-240 Mechanized Menace, OGN-255/OGN-303 Nine-Tailed Fox, SFD-199/SFD-248 Prodigal Explorer, UNL-197/UNL-234 Scorn of the Moon, VEN-151/VEN-195 Soul's Reflection, OGN-263/OGN-307 Swift Scout, UNL-181/UNL-226 Virtuoso.
Run play
Prerequisites
- THE WHOLE POINT IS THAT ONE SPELL PAYS BOTH, AND THE ONE WORD THAT DECIDES IT IS 'SPENT'. A 'costs N or more' clause reads the PRINTED cost and no discount touches it; an 'if you spent N or more' clause reads what left the Rune Pool (166.2, 203.1, 356.4.b). Both cards here are in the second family, so they fail together and succeed together — a discount that makes your 5-Energy spell cost 3 switches off the Library AND Jhin at once. Do not mix a cost-reduction package into this deck.
- AND THE [HIDDEN] PACKAGE PAYS NOTHING TO EITHER. 811.1.b plays a hidden card 'ignoring its base cost', so a hidden spell spends 0 and neither clause fires. The project measured this for the whole 'this turn' lens; the Library is a third member of the list.
- TWO PREDICTS PER JHIN, AND NEITHER OF THEM BURNS OUT. 436.4.a: predicting with too few cards in the deck does not Burn Out, and 431.1.c makes looking and revealing safe past the deck outright — 'does not Burn Out' — so the Library is the one card-selection engine that is safe to run with an empty Main Deck. 817.2 also stacks separate instances of [Vision], each choosing independently (817.2.a).
- PREDICT IS SELECTION, NOT ADVANTAGE. 436.1 is defined with 'look at', never 'reveal' (424.1 is public presentation), so it fires no 'as I'm revealed' payoff, and 416.1.a / 416.5 send a recycled card to the BOTTOM. This smooths draws; it does not add cards.
- THE LIBRARY HAS TO BE CONQUERED. 'While you control this battlefield' is the wording 190.6.d governs and 190.1 starts it uncontrolled. And 485.4.a / 485.5 / 486.5 / 103.4.c as for every battlefield entry.
- THE CHEAPEST WAY TO SPEND FOUR IS A SPELL THAT PAYS FOR ITSELF: any 4-Energy spell in the deck does the job, and the entry deliberately names none, because the condition is on the SPEND and not on the card. UNL-004 Prepared Neophyte (+4 Might on the same condition) is the third card in the family and a lead rather than a requirement.
Steps
- Take Forgotten Library and hold it. 190.1 starts it uncontrolled and 190.6.d ignores 'while you control this battlefield' until you do.
- In your Main Phase, play any spell paying 4 Energy or more out of the Rune Pool — spent, not printed (166.2, 203.1, 356.4.b).
- The Library triggers on that play and gives you a free [Predict]: look at the top card of your Main Deck and recycle it or leave it. 436.4.a keeps this safe even with almost nothing left in the deck.
- The same condition is now true for the turn, so play Jhin, Meticulous Killer for a single Mind Power instead of his 4 Energy.
- His [Vision] resolves as he enters (817.1.b, 817.1.c) for a second Predict, chosen independently of the first (817.2.a).
- Repeat any turn you cast a spell for 4 or more; the Library's half is unbounded, and Jhin's is capped at three copies (103.2.b).
Per iteration
one free Predict per qualifying spell, plus a 4-Energy 4-Might body for one Mind Power on the turn the condition is met
How it ends
engine only — deck smoothing and a discount, neither of which scores; the Library repeats forever, Jhin three times (103.2.b)
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 2026-09-07 (docs/phase0/walks/2026-09-07-uncatalogued-cards.md), issue #171 2026-09-07 record
How this entry was audited
REFUTE = a refutation pass, with its date and verdict · WOUNDED = the pass found a flaw and the entry was rewritten · BUDGETED = the pass checked the recycle-and-draw ledger · lens = the hunt that proposed it.
HAND-WALKED 2026-09-07, issue #171 — the first entry to use either card. Card text verbatim from data/corpus_flat.txt. Both cards were checked against the project's own split of the 'this turn' lens before they were paired: they are in the same half of it ('if you SPENT', which a discount switches off), which is what makes them fail and succeed together and is stated as a deckbuilding constraint rather than left implicit. Trap check: 436.4.a and 431.1.c are cited so the Predict is not mistaken for a Burn Out risk; 436.1 and 424.1 are cited so it is not mistaken for a reveal; 416.1.a / 416.5 are cited so recycling is not mistaken for card advantage; 190.1 + 190.6.d are cited because this battlefield DOES say 'you' and therefore has to be taken; exactly one battlefield is named, so 485.4.a is respected.
Walked against Core Rules 2026-07-16