Cheapest priced copy (Commander 2021): $0.49 at Card Kingdom, near mint, their price list as of .
Deathbringer Regent 
Creature — Dragon · 5/6 · Rare · Dragons of Tarkir · #96
Flying
When this creature enters, if you cast it from your hand and there are five or more other creatures on the battlefield, destroy all other creatures.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
8 printings · $0.49 to $1.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander 2017 | 110 | Rare | $0.59 | — |
| Commander 2021 | 141 | Rare | $0.49 | — |
| Dragons of Tarkir | 96 | Rare | $0.49 | $1.49 |
| Archenemy: Nicol Bolas | 32 | Rare | $0.49 | — |
| Jumpstart 2022 | 396 | Rare | $0.49 | — |
| New Capenna Commander | 246 | Rare | $0.49 | — |
| Dragons of Tarkir Promos | 96 | Rare | — | $0.49 |
| Dragons of Tarkir Promos | 96s | Rare | — | $1.49 |
2 rulings from Wizards of the Coast
- 25 February 2015If you cast a creature spell that enters the battlefield as a copy of Deathbringer Regent, the enters-the-battlefield ability will trigger (assuming the “five or more other creatures” requirement is also met).
- 25 February 2015Deathbringer Regent's last ability destroys all creatures except Deathbringer Regent, including the five other creatures required for the ability to have an effect.