Cheapest priced copy (Double Masters 2022): $0.59 at Card Kingdom, near mint, their price list as of .
Yahenni, Undying Partisan 
Legendary Creature — Aetherborn Vampire · 2/2 · Rare · The Lost Caverns of Ixalan Commander · #214
Haste
Whenever a creature an opponent controls dies, put a +1/+1 counter on Yahenni.
Sacrifice another creature: Yahenni gains indestructible until end of turn.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
11 printings · $0.59 to $6.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Double Masters 2022 | 99 | Rare | $0.59 | $2.49 |
| Double Masters 2022 | 445 | Rare | — | — |
| Aether Revolt | 74 | Rare | $0.79 | $1.99 |
| Commander Masters | 201 | Uncommon | $0.69 | $1.99 |
| The Lost Caverns of Ixalan Commander | 214 | Rare | $0.59 | — |
| Aether Revolt Promos | 74p | Rare | $4.49 | $6.99 |
| Aether Revolt Promos | 74s | Rare | — | $3.99 |
| The List | 2X2-99 | Rare | — | — |
| The List | AER-74 | Rare | $0.59 | — |
| Secrets of Strixhaven Commander | 232 | Rare | $0.59 | — |
| Tarkir: Dragonstorm Commander | 202 | Rare | $0.79 | — |
One ruling from Wizards of the Coast
- 9 February 2017If Yahenni and a creature an opponent controls die simultaneously (perhaps because they fought or were in combat together), Yahenni won't be on the battlefield as its triggered ability resolves. It can't be saved by the +1/+1 counter that would have been put on it.