Diamond Knight
Artifact Creature — Knight
Vigilance (Attacking doesn't cause this creature to tap.)
As this creature enters, choose a color.
Whenever you cast a spell of the chosen color, put a +1/+1 counter on this creature.
- CMC
- 3
- Mana cost
- Color identity
- C
- Rarity
- uncommon
- Set
- Core Set 2020
- Price
- $0.28
- EDHREC rank
- #14821
Diamond Knight enters the battlefield as a counter-accruing engine — pick the right color and every spell in that color loads it up, turning a two-mana artifact creature into a growing threat that also produces mana. The cost is total color dependency: in a deck that doesn't cast spells in one dominant color, Diamond Knight is just a 2/2 for two that taps for a color you might not even need.
Best Commanders
Commanders with the highest synergy
Dion, Bahamut's Dominant
Dion, Bahamut's Dominant triggers off Dragons and +1/+1 counters, and Diamond Knight feeds both sides of that loop — it grows on every colored spell cast, then plugs directly into Dion's counter-manipulation payoffs.
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 |
Diamond Knight is legal in Commander, Legacy, Modern, Pioneer, Vintage, and Oathbreaker, but Commander is the only format where it belongs. In Commander, a mono-color or heavily skewed two-color deck can pick a single color and reliably trigger it turn after turn, making the mana production meaningful and the counter accumulation real. In Modern or Pioneer, a 2/2 for two that requires you to cast spells in one color to become relevant is too slow and too parasitic — aggro doesn't want it, midrange has better value creatures, and combo doesn't need it. Legacy and Vintage move too fast for Diamond Knight to matter at all. Treat it as a Commander-only card.
Key Combos
Combo lines featuring this card
Price Context
Current price
$0.28 bulk tier
At $0.28, Diamond Knight is pure bulk — the floor tier. For the decks that actually want it, that price is fine; picking up a playset costs less than a dollar and the card does meaningful work in the right shell.
Explore
Sources
Mentioned
- Dion, Bahamut's Dominant
Updated . Data from Scryfall, EDHREC, and Commander Spellbook.