101Leafy researched the games.
Dual Battleaxe

Dual Axes based off of the poisonous Sword. Simple, yet highly-effective weapons.
| Class | Dual Blades |
|---|---|
| Rarity | 6 |
| Attack | 252 |
| Poison | 100 |
| Slots | 1 |
| Price | 70,000z |
Upgrades
| Upgraded from | Upper Battleaxe |
|---|---|
| Upgrades into | Dual Battleaxe+ |
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 714.
Materials
Rubbery Hide+ ×8, Hrd Monster Bone ×6, Toxin Sac ×6, Gypceros Head ×2