101Leafy researched the games.
Gale Horn Bow

Powerful Bow made from Black Diablos horn. One pull, and you'll sing its praises too.
A hunting bow whose frame is decorated with the horns that are practically the symbol of Diablos, calling to mind the proud "Horn King." The handle, said to be carved from the inside of Diablos shell, is several times stronger than that of a normal bow, and simply being able to draw its string earns praise from many hunters.
Our translation of 復刻 ハンター大全 (KADOKAWA / Enterbrain, 2014), page 175.
| Class | Bow |
|---|---|
| Rarity | 9 |
| Attack | 336 |
| Affinity | 20% |
| Defense | +30 |
| Slots | 0 |
| Table price | 90,100z |
Upgrades
| Upgraded from | Diablos Horn Bow II |
|---|---|
| Upgrades into | DiablosKingHornBow |
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 800.
Materials
HvyBlkBlosShell ×8, HvyDiablosSpine ×5, StoutBlkTwstdHrn ×3, Big Wyvern Stone ×2