101Leafy researched the games.
Fatalis Dual Blades

Infused with Black Dragon fury, these turn the user's arms into blades of death.
There is a story that even after its wielder died, his arms went on moving and cut down anything that came near. Because of this, the workshop strictly orders owners: "These dual blades are steeped in Fatalis's rage, so harbor no evil in your heart." It is also said they stir up an urge to cut something, whatever it may be.
Our translation of 復刻 ハンター大全 (KADOKAWA / Enterbrain, 2014), page 155.
| Class | Dual Blades |
|---|---|
| Rarity | 8 |
| Attack | 294 |
| Dragon | 350 |
| Affinity | -10% |
| Slots | 0 |
| Table price | 100,000z |
Upgrades
| Upgraded from | Black Twin Daggers |
|---|---|
| Upgrades into | Fatalis Dual Sky |
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 716.