Monsters are the non-player, attackables NPCs in OSO

Future Jungle LocationEdit

  • Mash Apes (aggressive)

monkeys covered with dark brown fur and malformed arms, with fists hard as stone. Usually found in packs (of 3)

West Edit

Plains Edit

  • Herbivores (non aggressive)

Drop : Fur

  • Sandman

Forest Edit

at night
  • Wild Dogs

Drops : Fangs, Dog Fur

  • Flying Bats

Drop : Poison Blood, membranes


  • Armadillos

Drops : Stone Scales

  • Rock Crab.

Drops : Rock Crab's meat

Boss : Golem, physical defence is high

Past 3rd Town

Mine Dungeon Edit

  • Arachne

Volcanic Area Edit

  • Magma Bear
  • Dust Moth
  • Dust Eater

*Volcanic Zone's Sweltering Oil

Demonfolk Resort Edit

  • Red Ogre and Blue Ogre
  • Goblin thug
  • armed hobgoblin
  • ogres

Challenge Arena Edit

  • Goblin thug
  • Goblin Soldier
  • Magma Bear
  • Hobgoblin Soldier
  • Hobgoblin Knight
  • Red Ogre and Blue Ogre
  • Urami-danuki
  • Twin-torso Warrior

East Edit


  • Big Boar

Drops : Big Boar's Meat, Fangs, Big Boar's Fur.

  • Goblins

Drops : Goblin's Horn

  • Slimes

Drops : Blue Jelly

Further :

  • Mill Bird
  • Grey Rat.

Crystal CaveEdit


  • Poison Dozers (Centipedes, 50cm wide)
  • Boss : Acid Dozer (like Centipede but x3 bigger). Saliva is acid
Drops (for the 2) : Venomous Insect's Shell, Acid Liquid
Collection points
  • Iron Ore
  • Fossil (random rare chance ?)

【Crystal Tree】's GardenEdit

The room behind the boss area. Unlike the rest of the cave, has an open ceiling and light floods from above. Contains a garden of flowers and a giant crystal tree, of which the players can harvest one branch as a reward.

Crystal Tree's Branch 【Important Item】

North Edit

Forest Edit


  • Mountain Apple

Mountain Edit


  • Mad Seed
  • Rafflesian
  • Aero Snake
  • Bunker Bee
  • Bunker Bee Queen


Highland Edit


  • Steel Cow
  • Iron Cow
  • Mage Goat
  • Warlock Goat
  • Cockatrice
  • Cockatrice King
  • Lightning Horse
  • Grand Rock



  • Cockatrice eggs

Inside Body Dungeon Edit


  • degenerated passage-trap organism
  • poison-paralysis parasite mob
  • death-throes bad-status-liquid mob
  • Fresh Bacteria
  • Electric Parasitic Insect


  • Meat pitfall
  • Shifting corridors


  • Water of Life

Unknown Location Edit



  1. vol1ch3