101Leafy researched the games.
Plesioth Wave Sword

High-maintenance topquality piece, many times stronger than a water beam.
| Class | Great Sword |
|---|---|
| Rarity | 9 |
| Attack | 1056 |
| Water | 400 |
| Slots | 1 |
| Price | 90,000z |
Upgrades
| Upgraded from | Plesioth Azureblade |
|---|---|
| Upgrades into | Plesioth Wave Blade |
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 682.