Cheapest priced copy (Kamigawa: Neon Dynasty): $0.49 at Card Kingdom, near mint, their price list as of .
Raiyuu, Storm's Edge 
Legendary Creature — Human Samurai · 3/3 · Rare · Kamigawa: Neon Dynasty · #232
First strike
Whenever a Samurai or Warrior you control attacks alone, untap it. If it's the first combat phase of the turn, there is an additional combat phase after this phase.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
6 printings · $0.49 to $3.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Kamigawa: Neon Dynasty | 232 | Rare | $0.49 | $0.49 |
| Kamigawa: Neon Dynasty | 329 | Rare | $2.29 | $2.99 |
| Kamigawa: Neon Dynasty | 491 | Rare | $0.59 | $0.79 |
| Kamigawa: Neon Dynasty Promos | 232★ | Rare | — | $1.99 |
| Kamigawa: Neon Dynasty Promos | 232p | Rare | $0.69 | $3.49 |
| Kamigawa: Neon Dynasty Promos | 232s | Rare | — | $0.59 |
2 rulings from Wizards of the Coast
- 18 February 2022A creature attacks alone if it's the only creature declared as an attacker during the declare attackers step. For example, Raiyuu's triggered ability won't trigger if you attack with multiple creatures and all but one of them are removed from combat.
- 18 February 2022Notably, the triggered ability doesn't give you any additional main phases. This means that you will move directly from the end of combat step of one combat phase to the beginning of combat step of the next one.