Riddlekeeper
Creature — Homunculus
Whenever a creature attacks you or a planeswalker you control, that creature's controller mills two cards.
- CMC
- 3
- Mana cost
- Color identity
- U
- Rarity
- rare
- Set
- Commander Anthology Volume II
- Price
- $12.53
- EDHREC rank
- #9870
Riddlekeeper taxes every spell an opponent casts with a mill trigger, and at under $13 it's the most mana-efficient mill-per-turn piece in blue. Pair it with Bruvac the Grandiloquent and every single spell your opponents cast mills them for four instead of two — the math gets ugly fast.
Best Commanders
Commanders with the highest synergy
Bruvac the Grandiloquent
Bruvac the Grandiloquent doubles any mill effect that hits exactly half a library, so every trigger from Riddlekeeper becomes four cards instead of two — one spell cast by any opponent can spiral into double-digit milling by late game.
The Mindskinner
The Mindskinner rewards stacking mill triggers from multiple sources, and Riddlekeeper fires on every spell across all three opponents, generating consistent mill pressure without requiring The Mindskinner to attack.
Phenax, God of Deception
Phenax, God of Deception builds around tapping creatures to mill, and Riddlekeeper contributes mill even on turns where you're tapping your board — it fills the gaps Phenax leaves when you're holding creatures back to block.
Format Analysis
Where it lives, where it can’t
| Format | Verdict |
|---|---|
| commander | legal |
| legacy | legal |
| modern | not legal |
| pioneer | not legal |
| standard | not legal |
| vintage | legal |
| pauper | not legal |
| oathbreaker | legal |
Commander is where Riddlekeeper earns its keep — three opponents casting spells every turn means the trigger fires constantly, and dedicated mill strategies in blue-black have enough redundancy to close games fast. In Legacy and Vintage, Riddlekeeper is technically legal but far too slow; dedicated mill decks in those formats have access to broken card velocity that makes a two-mana 1/1 irrelevant. Oathbreaker is the one other format where it sees occasional play, specifically in mill-focused signature spell builds that want every incremental trigger they can stack.
Key Combos
Combo lines featuring this card
Budget Alternatives
Cheaper options that do most of the same work
Hedron Crab does similar passive milling work for a single blue mana, firing on every land drop rather than every spell — it's under $1 and covers early game mill pressure Riddlekeeper can't. If you need the spell-trigger specifically, Maddening Cacophony is a clean $0.50 instant that mills eight or half a library, but it's a one-shot rather than a repeating engine, so you're trading consistency for burst.
Price Context
Current price
$12.53 mid tier
At $12.53, Riddlekeeper sits in the mid tier — justified for a card with no direct functional replacement in mill strategies that want passive, repeating triggers. It's a narrow card with a loyal home, so the price reflects low supply and consistent demand from Bruvac and Phenax brewers rather than broad format play.
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Sources
Updated . Data from Scryfall, EDHREC, and Commander Spellbook.