101Leafy researched the games.
AncientFatalisBuster

Giant white Hammer embodying the tremendous power of a Fatalis' ancestor.
| Class | Hammer |
|---|---|
| Rarity | 8 |
| Attack | 988 |
| Dragon | 350 |
| Defense | +8 |
| Slots | 0 |
| Price | 100,000z |
Upgrades
| Upgraded from | Black Hammer |
|---|---|
| Upgrades into | AncientFatalisRuiner |
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 726.