Feybreak Cavern

Who spawns

Common

StarryonLv 50–5418.2%SplatterinaLv 52–5618.2%TarantrissLv 52–5518.2%SmokieLv 50–5418.2%NyafiaLv 52–5618.2%

Bosses

Warsect TerraLv 56–585.6%OmasculLv 56–585.6%NitemaryLv 56–585.6%Foxparks CrystLv 50–585.6%Loupmoon CrystLv 56–585.6%Ribbuny BotanLv 50–585.6%Dazzi NoctLv 50–585.6%GildaneLv 56–585.6%Faleris AquaLv 56–585.6%Cryolinx TerraLv 56–585.6%PruneliaLv 50–585.6%SmokieLv 50–585.6%NyafiaLv 56–585.6%StarryonLv 56–585.6%SplatterinaLv 56–585.6%TarantrissLv 50–585.6%Caprity NoctLv 50–585.6%Kitsun NoctLv 56–585.6%

Chest loot

Ordinary chest

Gold Coin×3000–3500100%High Quality Bait×2–3100%Large Pal Soul40.2%Gatling Gun Ammo×1–325.2%Ultra Sphere×1–325.2%Mammorest Curry×1–225.2%Ultimate Sphere20.1%Gold Key16.1%Training Manual (XL)×1–214.6%Training Manual (L)×2–39.7%High Grade Medical Supplies4%High Quality Recovery Meds2.4%Laser Rifle Schematic 12.4%Flamethrower Schematic 12.4%Hexolite Armor Schematic 11.6%Hexolite Helmet Schematic 11.2%Cold Resistant Hexolite Armor Schematic 10.8%Heat Resistant Hexolite Armor Schematic 10.8%Rocket Launcher Schematic 10.8%Laser Rifle Schematic 20.5%Flamethrower Schematic 20.5%Hexolite Armor Schematic 20.3%Hexolite Helmet Schematic 20.2%Cold Resistant Hexolite Armor Schematic 20.2%Heat Resistant Hexolite Armor Schematic 20.2%Rocket Launcher Schematic 20.2%Life Pendant Schematic0.2%Attack Pendant Schematic0.2%Defense Pendant Schematic0.2%Pendant of Diligence Schematic0.2%Heat-Resistant Undershirt Schematic0.2%Thermal Undershirt Schematic0.2%Ring of Neutral Resistance Schematic0.2%Ring of Fire Resistance Schematic0.2%Ring of Water Resistance Schematic0.2%Ring of Electric Resistance Schematic0.2%Ring of Grass Resistance Schematic0.2%Ring of Ice Resistance Schematic0.2%Ring of Ground Resistance Schematic0.2%Ring of Dark Resistance Schematic0.2%Ring of Dragon Resistance Schematic0.2%Multiclimate Undershirt Schematic0.2%Ring of Freight Schematic0.2%Neutral Support Whistle Schematic0.2%Fire Support Whistle Schematic0.2%Water Support Whistle Schematic0.2%Electric Support Whistle Schematic0.2%Grass Support Whistle Schematic0.2%Ice Support Whistle Schematic0.2%Ground Support Whistle Schematic0.2%Dark Support Whistle Schematic0.2%Dragon Support Whistle Schematic0.2%Attack Support Whistle Schematic0.2%Defense Support Whistle Schematic0.2%Growth Acceleration Bell Schematic0.2%Laser Rifle Schematic 30.1%Flamethrower Schematic 30.1%Hexolite Armor Schematic 30.1%Laser Rifle Schematic 40%Flamethrower Schematic 40%Hexolite Helmet Schematic 30%Hexolite Helmet Schematic 40%Hexolite Armor Schematic 40%Cold Resistant Hexolite Armor Schematic 30%Cold Resistant Hexolite Armor Schematic 40%Heat Resistant Hexolite Armor Schematic 30%Heat Resistant Hexolite Armor Schematic 40%Rocket Launcher Schematic 30%Rocket Launcher Schematic 40%

Special chest

Gold Coin×3400–3700100%Futuristic Technical Manual32.3%Ancient Technical Manual×1–332.3%Xenolord Slab25.3%Treasure Map No. 510.1%

Dungeons of a biome are scattered across that region, but the game data has no 'this cave = this dungeon' map link — the entrance is assigned procedurally.