101Leafy researched the games.
Akantor Broadswrd S

Long Sword with the power of a black deity. Those with it feel otherworldly.
Its black blade and red lines call to mind the very form of the "Black God." Because its power is so overwhelming, the workshop strictly examines whether a user is fit to own it. For that reason, anyone who holds this long sword is said to be feared as "a being outside the laws of the world."
Our translation of 復刻 ハンター大全 (KADOKAWA / Enterbrain, 2014), page 148.
| Class | Long Sword |
|---|---|
| Rarity | 10 |
| Attack | 1584 |
| Affinity | 40% |
| Slots | 0 |
| Table price | 145,000z |
Upgrades
| Upgraded from | Akantor Katana |
|---|
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 696.