101Leafy researched the games.
Decider

Heavy Great Sword of high quality steel. Symbol of ancient judge's authority.
| Class | Great Sword |
|---|---|
| Rarity | 9 |
| Attack | 1104 |
| Slots | 0 |
| Price | 75,000z |
Upgrades
| Upgraded from | Carbalite Sword+ |
|---|---|
| Upgrades into | Punisher, Igneous Blade, Liquid 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 684.
Materials
Eltalite Ore ×10, Union Ore ×10, Emperor Cricket ×10, Monster Essence ×2