101Leafy researched the games.
Ancient Fatalis Lied

One night long ago, hundreds of listeners passed on from the songs played by this.
A hunting horn said to have caused the "Nightmare Opera," which in ancient times led an audience of several hundred to their deaths in a single night. Its dangerous tone is even said to creep up on people in places the sound does not reach, and not only to lead their hearts astray but to drive them straight to death.
Our translation of 復刻 ハンター大全 (KADOKAWA / Enterbrain, 2014), page 161.
| Class | Hunting Horn |
|---|---|
| Rarity | 8 |
| Attack | 1040 |
| Dragon | 330 |
| Defense | +8 |
| Slots | 0 |
| Notes | Purple, Green, Red |
| Table price | 100,000z |
Songs
| Notes | Song | Effect |
|---|---|---|
| Purple, Purple | Movement Speed Up | Faster movement with weapon drawn for 3 min *2 |
| Purple, Red, Red | Attack Up [Hi] | Attack +15% for 1 min 30 s |
| Red, Green, Red | Defense Up [Hi] | Defense +20% for 1 min 30 s |
| Purple, Green | Health Rec [Lo] | Restores 20 health (33% chance) or 10 (67%) |
| Green, Red, Green, Purple | Recover Spd Up [Hi] | Red health recovers 3× as fast for 2 min |
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 166.
Upgrades
| Upgraded from | Black Lute |
|---|---|
| Upgrades into | Ancient Fatalis Lute |
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 740.