101Leafy researched the games.
Liquid Fire Blade

Lavasioth Long Sword. Sharp and strong; breaks through rock like a torrent of lava.
| Class | Long Sword |
|---|---|
| Rarity | 9 |
| Attack | 1200 |
| Fire | 200 |
| Affinity | 10% |
| Slots | 1 |
| Price | 100,000z |
Upgrades
| Upgraded from | Decider |
|---|---|
| Upgrades into | Divine Fire Blade |
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 694.
Materials
ThckLavasiothScl ×8, HvyLavasiothShl ×6, Carbalite Ore ×10