101Leafy researched the games.
Plesioth Watersword

Bonecraft adds an elemental effect. Shoots high-pressure water from its cutting edge.
| Class | Great Sword |
|---|---|
| Rarity | 3 |
| Attack | 576 |
| Water | 390 |
| Slots | 0 |
| Price | 3,650z |
Upgrades
| Upgraded from | Finblade |
|---|---|
| Upgrades into | Plesioth Crystasword |
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 680.