101Leafy researched the games.
Halberd

Doesn't stay sharp long, but possesses superior Attack. A time-honored favorite.
| Class | Great Sword |
|---|---|
| Rarity | 4 |
| Attack | 864 |
| Slots | 0 |
| Price | 4,250z |
Upgrades
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 686.
Materials
Dragonite Ore ×8, Iron Ore ×30, Monster Bone+ ×2, Hercudrome ×3