Cheapest priced copy (Murders at Karlov Manor): $0.49 at Card Kingdom, near mint, their price list as of .
Yarus, Roar of the Old Gods 
Legendary Creature — Centaur Druid · 4/4 · Rare · Murders at Karlov Manor · #375
Other creatures you control have haste.
Whenever one or more face-down creatures you control deal combat damage to a player, draw a card.
Whenever a face-down creature you control dies, return it to the battlefield face down under its owner's control if it's a permanent card, then turn it face up.
Legal inCommanderBrawlStandardPioneerModernLegacyVintage
Not legal inPauper
4 printings · $0.49 to $0.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Murders at Karlov Manor | 245 | Rare | $0.49 | $0.49 |
| Murders at Karlov Manor | 375 | Rare | $0.49 | $0.79 |
| Murders at Karlov Manor Promos | 245p | Rare | $0.59 | $0.99 |
| Murders at Karlov Manor Promos | 245s | Rare | — | $0.79 |
4 rulings from Wizards of the Coast
- 2 February 2024Normally, combat damage is dealt all at the same time. In that case, Yarus, Roar of the Old Gods's last ability triggers once for each player that face-down creatures you control dealt combat damage to, regardless of how many creatures were dealing that damage. If any of those face-down creatures have double strike or first strike, the ability will trigger once for each player dealt damage in each combat damage step.
- 2 February 2024If a face-down creature dies but the permanent card it becomes in the graveyard leaves the graveyard before Yarus, Roar of the Old Gods's last ability resolves, it will not return to the battlefield.
- 2 February 2024If a permanent card that would be returned to the battlefield face down by Yarus, Roar of the Old Gods's last ability can't be turned face up for some reason, it'll still be returned to the battlefield, but it will stay face down. In that case, it will be a 2/2 creature with no name, mana cost, or creature types. Since it isn't disguised or cloaked, it won't have ward {2}.
- 2 February 2024If Yarus, Roar of the Old Gods dies at the same time as one or more face-down creatures you control, its last ability triggers for each of those creatures.