Cheapest priced copy (Streets of New Capenna): $0.49 at Card Kingdom, near mint, their price list as of .
Devilish Valet 
Creature — Devil Warrior · 1/3 · Rare · Streets of New Capenna · #105
Trample, haste
Alliance — Whenever another creature you control enters, double this creature's power until end of turn.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
5 printings · $0.49 to $3.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Bloomburrow Commander | 195 | Rare | $0.59 | — |
| Streets of New Capenna Promos | 105p | Rare | $0.79 | $1.49 |
| Streets of New Capenna Promos | 105s | Rare | — | $3.49 |
| Streets of New Capenna | 105 | Rare | $0.49 | $0.49 |
| Streets of New Capenna | 423 | Rare | $0.99 | $0.99 |
One ruling from Wizards of the Coast
- 29 April 2022To double a creature's power means that creature gets +X/+0, where X is its power as the ability resolves.