Where it is
The Mystic Castle stands on the Desert map, in the north-west of the world map, the same map as Desert City. Its monsters gather in four spots: (362,479), (388,371), (162,319) and (232,175).
Monsters
Three groups share the castle: bats, bull monsters and devils. Several of them, such as the Vampire Bat, the Vampire King and the Devil King, have 65,535 HP, so even the lowest spot here is a big jump from Bird Island.
| Picture | Monster | Level | HP | Coordinates |
|---|---|---|---|---|
 | Tomb Bat | 102 | 24472 | 362,479 |
 | Tomb Bat | 103 | 48944 | 362,479 |
 | Bloody Bat | 107 | 28140 | 388,371 |
 | Bloody Bat | 108 | 56280 | 388,371 |
 | Vampire Bat | 108 | 65535 | 388,371 |
| Bloody King | 110 | 28140 | 388,371 | |
| Vampire King | 113 | 65535 | 388,371 | |
 | Bull Monster | 112 | 35050 | 162,319 |
 | Bull Monster | 113 | 65535 | 162,319 |
 | Bull Devil | 115 | 35050 | 162,319 |
 | Red Devil | 117 | 60460 | 232,175 |
 | Red Devil | 118 | 65535 | 232,175 |
| Bloody Devil | 118 | 65535 | 232,175 | |
 | Devil King | 120 | 65535 | 232,175 |
 | Green Devil | 120 | 60460 | 232,175 |
Who should hunt here
This is the hunting ground for levels 102 to 120, after Bird Island. Start with the Tomb Bats and finish with the devils at (232,175), where the Devil King and the Green Devil reach level 120.
The official page points next to the Mystic Cave, home of more Devil Kings. The Labyrinth, with floors from level 105 to 125, is another option at this stage.
Sources
Game pictures: © TQ Digital / NetDragon · co.99.com