101Leafy researched the games.
Red Saber

A blade crafted from the flames of Rathalos. It carries a faint glow of red.
| Class | Sword |
|---|---|
| Rarity | 3 |
| Attack | 154 |
| Fire | 150 |
| Slots | 0 |
| Price | 1,560z |
Upgrades
| Upgraded from | Chief Kris |
|---|---|
| Upgrades into | Djinn, Corona, Flame Syphos, Twin Flames |
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 702.
Materials
FireWyvern Fluid ×4, Flame Sac ×2, Wyvern Fang ×2, Sm Monster Bone ×10