101Leafy researched the games.
ImperialThundersword

A blade that harnesses lightning and unleashes it into your victim's body.
| Class | Great Sword |
|---|---|
| Rarity | 10 |
| Attack | 1152 |
| Thunder | 640 |
| Slots | 0 |
| Price | 100,000z |
Upgrades
| Upgraded from | King Thundersword |
|---|
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 680.