From Medivia Online Wiki
Near City: Carlin
Location: Demona is hidden below mols to protect the city from bandits and warriors. This city is the home to many Warlock, Elf Arcanist and Stone Golem. There are several Quests-items located here.
Demona Main Room East Entrance Stairs: Lure one Warlock to the stairs by going to the corner where you plan to trap it in. Then quickly go down the right side of the stairs. Then go up the left side of the stairs to get behind the Warlock and trap it in the corner. Stand just north west of the Warlock untill it reaches half health points or yellow health points, then step south to block it in so the Warlock cannot run away.
Note: The left and right stairs are the 3 stairs of the east entrance, NOT the east/west entrances to the main room.
As mage it's really easy to kill these creatures. Using Sudden Death Runes on warlocks while stairjumping will kill the warlocks really fast without you receiving any damage. You rather want to do this with a blocker, but it's possible to solo them.
Path:In order to get there, you'll have to go through the Maze of lost Souls. Refer to Route Demona.