101Leafy researched the games.
Eternal Annihilator

Legendary dragon-killer. "Wield me true, and you will cut dragon scale like silk."
| Class | Great Sword |
|---|---|
| Rarity | 5 |
| Attack | 672 |
| Dragon | 520 |
| Slots | 1 |
| Price | 40,000z |
Upgrades
| Upgraded from | Dragonslayer |
|---|---|
| Upgrades into | Eternal Eradicator |
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 688.