Head east and be prepared to face all kinds of Orcs. (The safest route its marked with a blue line)
Down the stairs you will face several Orc Leaders, Orc Warlords, a Dragon and probably some Orc Shamans and Stone Golems coming from a room west of the staircase.
Head east after everything is killed.
In this room you will find several Orc Berserkers, Orc Warlords, Slimes, Orc Leaders and Orc Riders.
The quest boxes are located in the north end of this room.
Note: You will meet the Slime-shaped NPC The Orc King here. Do not say 'hi' to him, if you do he will summon a lot of Orcs of all types including Berserks, Leaders and Warlords.
