Cheapest priced copy (Tarkir: Dragonstorm Promos): $0.99 at Card Kingdom, near mint, their price list as of .
Teval, Arbiter of Virtue 
Legendary Creature — Spirit Dragon · 6/6 · Mythic · Tarkir: Dragonstorm · #230
Flying, lifelink
Spells you cast have delve. (Each card you exile from your graveyard while casting those spells pays for {1}.)
Whenever you cast a spell, you lose life equal to its mana value.
Legal inCommanderBrawlStandardPioneerModernLegacyVintage
Not legal inPauper
5 printings · $0.99 to $5.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Tarkir: Dragonstorm Promos | 230p | Mythic | $0.99 | $4.49 |
| Tarkir: Dragonstorm Promos | 230s | Mythic | — | $1.29 |
| Tarkir: Dragonstorm | 230 | Mythic | $0.99 | $0.99 |
| Tarkir: Dragonstorm | 319 | Mythic | $2.29 | $5.99 |
| Tarkir: Dragonstorm | 373 | Mythic | $2.29 | $5.99 |
2 rulings from Wizards of the Coast
- 4 April 2025“Delve” means “For each generic mana in this spell’s total cost, you may exile a card from your graveyard rather than pay that mana.” The delve ability isn’t an additional or alternative cost and applies only after the total cost of the spell with delve is determined.
- 4 April 2025If a spell on the stack has an {X} in its mana cost, use the value of X chosen as it was cast to determine that spell’s mana value.