Yakushima Dungeon

Who spawns

Common

Red SlimeLv 36–4110.4%Purple SlimeLv 36–4110.4%Cave BatLv 36–4110.4%Illuminant SlimeLv 42–4410.4%Illuminant BatLv 42–4410.4%Enchanted SwordLv 42–4410.4%Green SlimeLv 33–355.2%Blue SlimeLv 33–355.2%Demon EyeLv 33–355.2%Rainbow SlimeLv 42–443.5%Killamari PrimoLv 42–442.8%StarryonLv 42–442.8%IcelynLv 42–442.8%TombatLv 36–382.4%JellroyLv 39–411.7%ShroomerLv 39–411.7%Shroomer NoctLv 39–411.7%HerbilLv 33–351%DazziLv 33–351%Dumud GildLv 33–350.7%

Bosses

Eye of CthulhuLv 45100%

Chest loot

Ordinary chest

Hallowed Bar×4–10100%Coarse Ammo×5–1035%Giga Sphere×1–235%Training Manual (L)×1–219%Medium Pal Soul×1–217.7%Training Manual (XL)11%Gold Coin×2000–250010.6%Hyper Sphere8.8%Silver Key7.1%Excalibur Schematic7.1%Hallowed Mask Schematic7.1%Hallowed Headgear Schematic7.1%Hallowed Plate Mail Schematic7.1%Hallowed Helmet Schematic7.1%Hallowed Hood Schematic7.1%Medical Supplies1.8%Excalibur Schematic 11.4%Hallowed Mask Schematic 11.4%Hallowed Headgear Schematic 11.4%Hallowed Plate Mail Schematic 11.4%Hallowed Helmet Schematic 11.4%Hallowed Hood Schematic 11.4%Recovery Meds1.1%Excalibur Schematic 20.3%Hallowed Mask Schematic 20.3%Hallowed Headgear Schematic 20.3%Hallowed Plate Mail Schematic 20.3%Hallowed Helmet Schematic 20.3%Hallowed Hood Schematic 20.3%Excalibur Schematic 30.1%Hallowed Mask Schematic 30.1%Hallowed Headgear Schematic 30.1%Hallowed Plate Mail Schematic 30.1%Hallowed Helmet Schematic 30.1%Hallowed Hood Schematic 30.1%Excalibur Schematic 40%Hallowed Mask Schematic 40%Hallowed Headgear Schematic 40%Hallowed Plate Mail Schematic 40%Hallowed Helmet Schematic 40%Hallowed Hood Schematic 40%

Special chest

Celestial Sigil Schematic100%Hallowed Bar×20–40100%Futuristic Technical Manual33%Ancient Technical Manual×1–333%Terraprisma Schematic8.5%Vortex Beater Schematic8.5%Nightglow Schematic8.5%Terra Blade Schematic8.5%Applied Kindling Handbook I8.3%Applied Watering Handbook I8.3%Applied Planting Handbook I8.3%Applied Generating Electricity Handbook I8.3%Applied Handiwork Handbook I8.3%Applied Gathering Handbook I8.3%Applied Lumbering Handbook I8.3%Applied Mining Handbook I8.3%Applied Medicine Production Handbook I8.3%Applied Cooling Handbook I8.3%Applied Transporting Handbook I8.3%Applied Ranching Handbook I8.3%Terraprisma Schematic 16%Vortex Beater Schematic 16%Nightglow Schematic 16%Terra Blade Schematic 16%Terraprisma Schematic 24.5%Vortex Beater Schematic 24.5%Nightglow Schematic 24.5%Terra Blade Schematic 24.5%Terraprisma Schematic 33.5%Vortex Beater Schematic 33.5%Nightglow Schematic 33.5%Terra Blade Schematic 33.5%Terraprisma Schematic 42.5%Vortex Beater Schematic 42.5%Nightglow Schematic 42.5%Terra Blade Schematic 42.5%Skill Fruit: Pal Blast1.1%Skill Fruit: Power Bomb1.1%Skill Fruit: Implode1.1%Grass Skill Fruit: Solar Blast1.1%Grass Skill Fruit: Grass Tornado1.1%Grass Skill Fruit: Spine Vine1.1%Grass Skill Fruit: Seed Mine1.1%Water Skill Fruit: Hydro Laser1.1%Water Skill Fruit: Aqua Burst1.1%Water Skill Fruit: Acid Rain1.1%Water Skill Fruit: Bubble Blast1.1%Fire Skill Fruit: Ignis Rage1.1%Fire Skill Fruit: Ignis Breath1.1%Fire Skill Fruit: Flare Storm1.1%Fire Skill Fruit: Fire Ball1.1%Electric Skill Fruit: Lightning Bolt1.1%Electric Skill Fruit: Tri-Lightning1.1%Electric Skill Fruit: Lock-on Laser1.1%Electric Skill Fruit: Lightning Strike1.1%Ground Skill Fruit: Rock Lance1.1%Ground Skill Fruit: Sand Tornado1.1%Ground Skill Fruit: Stone Blast1.1%Ice Skill Fruit: Blizzard Spike1.1%Ice Skill Fruit: Iceberg1.1%Ice Skill Fruit: Crystal Breath1.1%Dark Skill Fruit: Nightmare Ball1.1%Dark Skill Fruit: Dark Laser1.1%Dark Skill Fruit: Poison Blast1.1%Dragon Skill Fruit: Dragon Meteor1.1%Dragon Skill Fruit: Dragon Burst1.1%Dragon Skill Fruit: Dragon Breath1.1%

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.