101Leafy researched the games.
Double Dragon

The Dragon element infused in these Dual Blades hits enemies from both sides.
| Class | Dual Blades |
|---|---|
| Rarity | 5 |
| Attack | 210 |
| Dragon | 220 |
| Slots | 0 |
| Price | 20,000z |
Upgrades
| Upgraded from | Black Sword |
|---|---|
| Upgrades into | Dual Dragon Ultimus |
Upgrade tree from モンスターハンターポータブル 2nd G 公式ガイドブック (Enterbrain, 2008), page 714.