101Leafy researched the games.
Rusted Great Sword

A rusty weapon that isn't good for much as-is. But if you polish it...
| Class | Great Sword |
|---|---|
| Rarity | 1 |
| Attack | 432 |
| Slots | 0 |
| Table price | 1,250z |
Upgrades
| Upgrades into | Tarnished Great Swd |
|---|
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 686.