Inquisitor Greyfax costs {1}{W}{U}{B} and is a 3/3 with vigilance. Other creatures you control get +1/+0 and have vigilance, and for {1} and a tap she taps target creature an opponent controls and investigates. Every turn she makes a Clue and taps a blocker.
The precon already has the Warhammer payoffs, including Inquisitor Eisenhorn, Marneus Calgar, Deny the Witch, Mortify and Belisarius Cawl. Each swap below pairs a cut with an add, and every card is scored with the same numbers the Oracle uses to build decks: synergy and inclusion from the Greyfax decks, plus lift, which shows how much more often a card turns up in Greyfax decks than in decks that could play it. Scores are lower than usual, because only a couple of thousand Greyfax decks exist.
Looking for the unmodified list first? Read the Forces of the Imperium precon guide.
What is holding the deck back
Not enough cheap Clue makers
Erdwal Illuminator, Teysa, Opulent Oligarch, Piper Wright, Officious Interrogation and Ethereal Investigator all investigate for two to four mana, and Tamiyo's Journal does it every upkeep. They are among the top-scoring cards the precon leaves out.
Few Clue payoffs
Tangletrove Kelp turns Clues into 6/6 creatures, Merchant of Truth gives them exalted, and Five Hundred Year Diary taps for mana for each Clue.
Big creatures and Vehicles that do not make Clues
Arco-Flagellant, Cybernetica Datasmith, Neyam Shai Murad and Redemptor Dreadnought are not cards Greyfax, and Knight Paladin, Grey Knight Paragon, Sanguinary Priest and Thunderwolf Cavalry are each played in about one deck in seven decks usually play.
The 11 swaps
Each pair shows the numbers for the card coming out and the card going in. Click a card image to zoom.
Arco-Flagellant is a 3/1 Human for {2}{B} with squad that cannot block. It is not a card Greyfax decks usually play.
Erdwal Illuminator is a 1/3 flier for {1}{U}. Whenever you investigate for the first time each turn, you investigate an additional time. Greyfax's ability makes two Clues, and it is the highest-scoring card the precon leaves out.
Cybernetica Datasmith is a 0/1 artifact creature for {1}{U}{B} that gives another player a 4/4 Robot. It is not a card Greyfax decks usually play.
Tamiyo's Journal costs {5}. At the beginning of your upkeep you investigate, and for a tap and three Clues you search your library for a card. A Clue every turn, and a tutor at the end.
Neyam Shai Murad is a 3/3 Human Rogue for {2}{W}{B} whose combat damage trades graveyard permanents. It is not a card Greyfax decks usually play.
Teysa, Opulent Oligarch is a 2/3 deathtouch creature for {1}{W}{B}. At your end step you investigate for each opponent who lost life this turn, and whenever a Clue goes to the graveyard you create a 1/1 flying Spirit, once each turn. A Clue maker that makes fliers when you crack Clues.
Redemptor Dreadnought is a five-mana 4/4 artifact creature with trample. It is not a card Greyfax decks usually play.
Forensic Gadgeteer is a 2/3 Detective for {2}{U}. Whenever you cast an artifact spell you investigate, and activated abilities of artifacts you control cost {1} less, to a minimum of one mana. Clues cost {1} to crack.
Knight Paladin is a five-mana 6/6 Vehicle that deals 4 damage to each opponent when it enters. It is played in about one Greyfax deck in eight.
Officious Interrogation costs {W}{U} at instant speed. You investigate X times, where X is the number of creatures controlled by the target players, and it costs {W}{U} more for each target beyond the first. Target yourself and you get a Clue for every creature you control.
Grey Knight Paragon is a 4/4 flash creature for {4}{W} that destroys an attacker. It is played in about one Greyfax deck in seven.
Tangletrove Kelp is a 6/6 artifact creature for {5}{U}{U} with ward {2}. At the beginning of each combat, other Clues you control become 6/6 Plant creatures until end of turn, and for {2} and a sacrifice you draw a card. Every Clue is a 6/6 attacker.
Sanguinary Priest is a 2/4 lifelink Astartes Cleric for {3}{B} that pings when your creatures die. It is played in about one Greyfax deck in seven.
Ethereal Investigator is a 2/3 flier for {3}{U}. When it enters you investigate once for each opponent, and whenever you draw your second card each turn you create a 1/1 flying Spirit. A flier that makes Clues and Spirits.
Thunderwolf Cavalry is a 4/4 first strike creature for {4}{W} that puts counters on your other creatures. It is played in about one Greyfax deck in seven.
Piper Wright, Publick Reporter is a 1/2 Human Detective for {1}{U}. Whenever she deals combat damage to a player you investigate that many times, and whenever you sacrifice a Clue you put a +1/+1 counter on target creature. A two-drop that turns Clues into counters.
Sister Repentia is a five-mana 5/1 Human Warrior that draws two cards when it dies. It is played in about one Greyfax deck in six.
Merchant of Truth is a 2/5 flying Angel Detective for {2}{W}{W}. Whenever a nontoken creature you control dies you investigate, and Clues you control have exalted. A flier that makes a Clue when your creatures die.
Sister of Silence is a 3/3 flash creature for {4}{U} that counters an instant, sorcery or ability. It is played in about one Greyfax deck in six.
Five Hundred Year Diary is a legendary artifact Clue for {3}{U} that enters tapped and taps for {U} for each Clue you control. A Clue that pays for the Clues, and draws a card when you sacrifice it.
Reaver Titan is a seven-mana 10/10 Vehicle with crew 4 that deals 5 damage to each opponent when it attacks. It is played in about one Greyfax deck in seven.
Academy Manufactor is a three-mana 1/3 artifact creature. If you would create a Clue, Food or Treasure token, you create one of each instead. Inquisitor Greyfax investigates every turn, so each Clue becomes a Clue, a Food and a Treasure. It is the highest-scoring card the precon leaves out.
The full swap list
Cut
- Arco-Flagellant
- Cybernetica Datasmith
- Neyam Shai Murad
- Redemptor Dreadnought
- Knight Paladin
- Grey Knight Paragon
- Sanguinary Priest
- Thunderwolf Cavalry
- Sister Repentia
- Sister of Silence
- Reaver Titan
Add
- Erdwal Illuminator
- Tamiyo's Journal
- Teysa, Opulent Oligarch
- Forensic Gadgeteer
- Officious Interrogation
- Tangletrove Kelp
- Ethereal Investigator
- Piper Wright, Publick Reporter
- Merchant of Truth
- Five Hundred Year Diary
- Academy Manufactor
What to keep
These cards are doing the deck's heavy lifting. Do not cut them.
- Inquisitor Eisenhorn$0.47
Played in 50% of Greyfax decks. Makes a 4/4 flying Demon when you reveal an instant or sorcery, and investigates when it connects. - Marneus Calgar
A double strike creature that draws whenever tokens enter, including Clues. - Deny the Witch$0.95
Counters a spell or ability, and its controller loses life equal to your creatures. - Mortify$0.20
Destroys a creature or enchantment at instant speed. - Belisarius Cawl$0.38
Taps two artifacts, including Clues, to create a 2/2 Warrior with vigilance.
If you want to spend more
These are strong but sit outside a budget upgrade. Prices are the cheapest paper printing.
- Search the Premises$0.27
Investigates whenever a creature attacks you or your planeswalkers. It costs more than a budget upgrade should. - Junk Winder$0.32
Costs less for each token you control and taps down permanents when tokens enter. - Mirkwood Bats$0.90
Drains each opponent whenever you create or sacrifice a token.
Forces of the Imperium already has the Warhammer payoffs. The upgrade is cheap Clue makers, and the cards that reward a table full of Clues, in place of expensive creatures and Vehicles that make none. These eleven swaps cost about $13 in total.
Want a full 100-card list built around Inquisitor Greyfax from today's data?
Build with The Oracle →Frequently asked questions
What are the best upgrades for the Forces of the Imperium precon?
Using data from 2,706 Inquisitor Greyfax decks, the highest-scoring additions are Academy Manufactor (for Reaver Titan), Erdwal Illuminator (for Arco-Flagellant) and Tamiyo's Journal (for Cybernetica Datasmith). The full list has 11 swaps, each scored with synergy, inclusion and lift.
How much does it cost to upgrade Forces of the Imperium?
All 11 swaps cost about $13.34 at the cheapest paper printings (TCGplayer market prices via Scryfall, 2026-10-27). If you want to spend more, the guide also covers Search the Premises ($0.27), Junk Winder ($0.32) and Mirkwood Bats ($0.90).
What should I cut from Forces of the Imperium?
The weakest cards for this commander are Arco-Flagellant, Cybernetica Datasmith and Neyam Shai Murad. The guide explains the reason for every cut, and swaps each one for a card that scores higher.
Which cards should I keep in Forces of the Imperium?
Keep Inquisitor Eisenhorn, Marneus Calgar, Deny the Witch, Mortify and Belisarius Cawl. These are the cards doing the deck's heavy lifting.
What does Inquisitor Greyfax do?
Inquisitor Greyfax costs {1}{W}{U}{B} and is a 3/3 with vigilance. Other creatures you control get +1/+0 and have vigilance, and for {1} and a tap she taps target creature an opponent controls and investigates. Every turn she makes a Clue and taps a blocker.
More Warhammer 40,000 Commander upgrade guides
How the numbers work
Inclusion is the share of Inquisitor Greyfax decks (2,706 of them when this was written, 2026-10-27) that play the card. Synergy is how much more often they play it than other decks in the same colours. Oracle score is synergy × 0.6 plus inclusion × 0.4, the same blend The Oracle uses to rank cards for a deck. Lift compares how often the card appears in these decks with how often it could, capped at 8× here; it is shown for context and does not change the score.
Two cautions. Players who run the precon unmodified count as Inquisitor Greyfax decks, which flatters every card the precon contains. Lift is high for many Clue cards because few decks play them outside a Clue deck, so use lift to compare cards, not to judge one in isolation. A card the commander's decks do not usually play counts as 0 in the average score. Prices are the cheapest non-foil paper printing on TCGplayer (via Scryfall), in USD, and move daily.