101Leafy researched the games.
Lost Black Katana

Legends say that by merely landing on its supreme edge a bug will be cut in two.
| Class | Long Sword |
|---|---|
| Rarity | 9 |
| Attack | 1008 |
| Affinity | 10% |
| Defense | +10 |
| Slots | 2 |
| Price | 80,000z |
Upgrades
| Upgraded from | Black Katana Mk.III |
|---|---|
| Upgrades into | Final Black Katana |
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 692.
Materials
Hornet Razorwing ×10, Vspoid Razorwing ×10, Monster Broth ×10, Emperor Cricket ×8