Monsters are the non-player, attackables NPCs in OSO
- Mash Apes (aggressive)
monkeys covered with dark brown fur and malformed arms, with fists hard as stone. Usually found in packs (of 3 in the tutorial leve)
- Herbivores (non aggressive)
Drop : Fur
- at night
- Wild Dogs
Drops : Fangs, Dog Fur
- Flying Bats
Drop : Poison Blood, membranes
Drops : Stone Scales
- Rock Crab.
Drops : Rock Crab's meat
Boss : Golem, physical defence is high
- Big Boar
Drops : Big Boar's Meat, Fangs, Big Boar's Fur.
Drops : Goblin's Horn
Drops : Blue Jelly
- Mill Bird
- Grey Rat.
- 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】