Elder Deep-Fiend
Creature — Eldrazi Octopus
Flash
Emerge 
(You may cast this spell by sacrificing a creature and paying the emerge cost reduced by that creature's mana value.)
When you cast this spell, tap up to four target permanents.
- CMC
- 8
- Mana cost
- Color identity
- U
- Rarity
- rare
- Set
- Modern Horizons 3 Commander
- Price
- $0.24
- EDHREC rank
- #7213
Elder Deep-Fiend enters the battlefield and immediately taps down four of an opponent's permanents — at instant speed, off an Emerge cost that can be as low as six mana if you sacrifice the right creature. Kiora, Sovereign of the Deep cheats it into play for free off her triggered ability, which turns that tap-four effect into a zero-mana tempo swing that can lock an opponent out of their combat step entirely.
Best Commanders
Commanders with the highest synergy
Kiora, Sovereign of the Deep
Kiora, Sovereign of the Deep tutors up Elder Deep-Fiend directly from the top of the library whenever a Kraken, Leviathan, Octopus, or Serpent enters under her control, letting you chain Elder Deep-Fiend triggers repeatedly to keep opponents' boards tapped out.
Runo Stromkirk
Runo Stromkirk flips into Krothuss once a large creature enters, and Elder Deep-Fiend sits comfortably in the tribe — it's a Kraken that Emerge-cheats in at instant speed, meaning it can tap down blockers or mana sources right before Runo's attack step.
Arixmethes, Slumbering Isle
Arixmethes, Slumbering Isle produces massive green mana once its slumber counters are cleared, and that burst of mana makes Emerge on Elder Deep-Fiend trivially affordable — you can cast it on the same turn you untap Arixmethes for the first time.
Format Analysis
Where it lives, where it can’t
| Format | Verdict |
|---|---|
| commander | legal |
| legacy | legal |
| modern | legal |
| pioneer | legal |
| standard | not legal |
| vintage | legal |
| pauper | not legal |
| oathbreaker | legal |
In Commander, Elder Deep-Fiend is a tempo piece rather than a finisher — tapping four permanents at instant speed can neutralize a table threat or steal a combat step, and Emerge keeps the cost flexible. In Modern and Pioneer, it saw play in Emerge-based shells that sacrificed smaller creatures to deploy it ahead of curve, though the power level of those formats has since pushed past what a single tap-four effect can realistically close out. Legacy has the raw speed to make even cheap Emerge costs feel slow, so Elder Deep-Fiend rarely shows up there outside of dedicated creature-chaining brews. Oathbreaker can get some mileage out of it in blue-green shells with sacrifice fodder, but it's Commander where the repeated-tap angle against multiple opponents genuinely punishes unprepared boards.
Key Combos
Combo lines featuring this card
Price Context
Current price
$0.24 bulk tier
At $0.24, Elder Deep-Fiend is firmly bulk — the kind of card you pick up as a throw-in without thinking twice. That price is unlikely to move significantly given the card's narrow competitive footprint, but for Commander purposes you're getting real on-board impact for essentially nothing.
Explore
Sources
Mentioned
- Kiora, Sovereign of the Deep
- Runo Stromkirk
- Arixmethes, Slumbering Isle
Updated . Data from Scryfall, EDHREC, and Commander Spellbook.