A Dark Ohm - Act 2 Side Quest
Location: Aman'lu/Vai'kesh Forest
Closest Portal: Vai'kesh Forest (South)
Objective: Witness the Vai'kesh ritual
Reward: Chant of the Dead
A Dark Ohm begins by speaking with Mage Lyssanore in the town of Aman'lu (Act 2). This Side Quest is arguably the most important one for you to complete in the entire game because it'll give you Chant of the Dead which allows you to converse with dead spirits. Being able to speak with dead spirits is required in order to complete many of the other available Side Quests.
What you'll need to do for this quest is to visit a location in The Vai'kesh Forest where some Vai'kesh are having a ritual. To find this location take the Teleporter to Vai'kesh Forest (South) and go directly north from where you port in at.
All you need to do is enter the area and see the scene below to update the quest. It doesn't matter if you interrupt their ritual or not, although there is some extra loot to be found in their room as well as the Lectern for Chant of Fortification. If you need help finding where this cave is check my map screenshot below.