101Leafy researched the games.
Hidden Saber

A very dark Long Sword. It cuts best in trained hands. How its made is a secret.
| Class | Long Sword |
|---|---|
| Rarity | 7 |
| Attack | 912 |
| Affinity | 40% |
| Slots | 1 |
| Price | 80,000z |
Upgrades
| Upgraded from | Tigrex Tooth |
|---|---|
| Upgrades into | Shadow of the Moon |
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 696.
Materials
NargaCuttingWing ×5, Black Narga Pelt ×5, Narga Brain Stem ×1, Carbalite Ore ×5