101Leafy researched the games.
Slaughter

Axe once used by a viciously inhumane king. Contains a millennium's worth of venom.
| Class | Great Sword |
|---|---|
| Rarity | 6 |
| Attack | 816 |
| Poison | 420 |
| Affinity | 10% |
| Slots | 0 |
| Price | 65,000z |
Upgrades
| Upgraded from | Rooster Decapitator |
|---|---|
| Upgrades into | Slaughter+ |
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 682.
Materials
Rubbery Hide+ ×5, Pur Gypceros Wng ×5, Hrd Monster Bone ×10, Gypceros Head ×2