| Name | Attribute | Level | Type |
|---|---|---|---|
| Osprae | - | 87 | Elite Monster |
| Osprae | - | 135 | Elite Monster |
| Osprae | - | 64 | Elite Monster |
| Osprae | - | 65 | Elite Monster |
| Osprae | - | 86 | Elite Monster |
| Osprae | - | 66 | Elite Monster |
| Ossifighter Boney Prince Charlie | 56 | Elite Monster | |
| Otherworld Judge Frasho | 72 | Boss Monster | |
| Otherworld Walker Crime | 65 | World Boss | |
| Otherworld Walker Punishment | 65 | World Boss | |
| Otherworldly Eye Demon | - | 1 | General Monster |
| Otherworldly Goblin | - | 1 | General |
| Otherworldly Goblin | 83 | General Monster | |
| Otherworldly Goblin Grandmaster | 80 | General Monster | |
| Out of control cavalry | 58 | General Monster | |
| Out of control cavalry | 58 | General Monster | |
| Out of control fighter | 58 | General Monster | |
| Out of control fighter | 58 | General Monster | |
| Out of control mercenary | 58 | General Monster | |
| Out of control mercenary | 58 | General Monster | |
| Outer Box 1 | - | 1 | Interactive |
| Outer Box 10 | - | 1 | Interactive |
| Outer Box 11 | - | 1 | Interactive |
| Outer Box 12 | - | 1 | Interactive |
| Outer Box 2 | - | 1 | Interactive |
| Outer Box 3 | - | 1 | Interactive |
| Outer Box 4 | - | 1 | Interactive |
| Outer Box 5 | - | 1 | Interactive |
| Outer Box 6 | - | 1 | Interactive |
| Outer Box 7 | - | 1 | Interactive |
| Outer Box 8 | - | 1 | Interactive |
| Outer Box 9 | - | 1 | Interactive |
| Outpost Human Soldier | - | 1 | General |
| Outpost Oak's Elven Soldier | - | 1 | General |
| Overloading Electrosphere | - | 61 | Elite Monster |
| Overloading Electrosphere | - | 61 | Elite Monster |
| Ovine Overlord Otis | - | 40 | Elite Monster |
| Owl | 11 | General Monster | |
| Pagan Puppetmaster Kiazach | 69 | Elite Monster | |
| Pagan Puppetmaster Kiazach | - | 59 | Elite Monster |
| Pagan Puppetmaster Kiazach | 59 | Elite Monster | |
| Pagan Puppetmaster Kiazach | 69 | Elite Monster | |
| Pagan Puppetmaster Kiazach | 59 | Elite Monster | |
| Painter Saffron | - | 1 | General |
| Painter Saffron | - | 1 | General |
| Painter Saffron | - | 1 | General |
| Painter Saffron | - | 1 | General |
| Painter Saffron | - | 1 | General |
| Paleotron | 59 | General Monster | |
| Paleotron Captain Landreau | 59 | Boss Monster |