If you follow the AoE setup with a Warlord, go to the following locations depending on your level:

• Levels 1-20:

Kamael Village / Gludio
(Main Quests).

• Levels 20-40:

Dion Ruins or Ant Nest
(in the first rooms).

• Levels 40-52:

Cruma Tower (Floor 1, then Floor 2).
Huge rooms with many mobs.

• Levels 52-61:

The Cemetery (outside Aden) or Dragon Valley (at the entrance).

• Levels 61-73:

Valley of Saints or Ancient Laboratory
(inside Cruma Tower, 3rd floor).

• Levels 73–80:

Forge of Gods (FOG) or Imperial Tomb (IT).
XP gains here are rapid if the Warlord has good armor.

• Levels 80-85:

Dragon Valley (DV)
(at AoE spots with skeletons) or
Monastery of Silence (MOS).