101Leafy researched the games.
Aqua Guardian

Advanced water Long Sword. Crafting technique found in ancient sunken ruins.
| Class | Long Sword |
|---|---|
| Rarity | 9 |
| Attack | 1104 |
| Water | 300 |
| Slots | 2 |
| Price | 90,000z |
Upgrades
| Upgraded from | Imperial Sword |
|---|---|
| Upgrades into | Atlantica, Edelweiss Ice Blade |
Can also be made new at the smithy.
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 694.
Materials
Purecrystal ×5, Union Ore ×20, Basarios Tears ×3, Eltalite Ore ×12