The Spreading Darkness is a quest that becomes available at the start of Act 3, which sets you on a path to finding Lorath.
Lorath previously instructed you to meet him at Ked Bardu, but once you find him, things will be a bit messy as it seems he has bad habits.
You will need to head to Ked Bardu to join up with Lorath so the two of you may continue searching for Lilith and find a way to put a stop to her evil.
How To Get The Spreading Darkness Quest?
The Spreading Darkness becomes available once you obtain Act 3: The Making of Monsters and will be the first quest that you need to complete.
The quest requires that you hit level 15 first and once you are ready, you will need to go to Ked Bardu to search for Lorath.
The Spreading Darkness Objectives
1) Meet Lorath in Ked Bardu
Make your way to Ked Bardu to start looking for Lorath and once you reach the area, his location will be marked on your map. (Yellow Quest Marker)
Search for Lorath in Ked Bardu
Head over to Lorath’s location and you will find a group of people around him, which later reveals that he has been drunk for quite some time.
2) Speak with Daruuk
Once you reach a snoring Lorath, you will be able to speak with a man named Daruk, who will explain what has been happening.
It seems that Lorath had been heavily drinking while shouting and cursing due to what seem to have been during his nightmares.
3) Rouse Lorath from his slumber
After the conversation with Daruuk, they will leave and you will need to interact with Lorath to wake him up, which starts a cutscene.
Lorath will inform you about what has happened starting from the day he first arrived in Ked Bardu as he searched for the Pale Man.
4) Speak with Teckrin
Lorath instructs you to speak with Teckrin to ask if she has heard anything from the Orbei Monastery as he had her send a message.
It is revealed that upon arriving in Ked Bardu, Lorath had her send a message to them but still has had no response from them.
Teckrin’s location will be marked on your map and you will need to speak with her before returning to Lorath with the update.
5) Return to update Lorath
After speaking to Teckrin, who has not heard any updates, you will need to speak to Lorath back where you first found him.
Teckrin will however have given you information regarding rumors of a Pale Man going through the Abahru Canyons.
You will need to speak to Lorath, who will let you decide whether to check the canyons first or visit the Orbei Monastery.
The Spreading Darkness Quest Rewards
After returning to Lorath to update him, you will be rewarded with XP and Gold and will receive two quests that you can choose from next.
Completing the Spreading Darkness will give you the Whittling Sanity and Suffering Disquiet quests, which are part of Act 3.
Verdict
It turns out that Lorath has been drinking himself to sleep for the past few days while waiting for a reply from the Orbei Monastery.
Lortath was surprised by the rumor of the Pale Man being seen and is eager to find him as soon as possible and will wait for you there.
Aside from meeting up with Lorath to search for the Pale Man, you will also need to check the Orbei Monastery when possible.
