101Leafy researched the games.
Diablos Maul

Improved Skullcrusher. A treasured Hammer made from a Diablos Tail.
| Class | Hammer |
|---|---|
| Rarity | 4 |
| Attack | 832 |
| Defense | +4 |
| Slots | 0 |
| Price | 4,250z |
Upgrades
| Upgraded from | Skullcrusher+ |
|---|---|
| Upgrades into | Finishing Hammer |
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 724.
Materials
Diablos Tail ×1, Monoblos Shell ×4, Eldr Dragon Bone ×2, Earth Crystal ×20