101Leafy researched the games.
Thunderlance

Endlessly releases Thunder. A power that can reduce the world to ashes.
| Class | Lance |
|---|---|
| Rarity | 8 |
| Attack | 391 |
| Thunder | 500 |
| Slots | 0 |
| Price | 60,000z |
Upgrades
| Upgraded from | Thunderspear |
|---|---|
| Upgrades into | Naar Thunderlance |
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 748.