An Inside Source - Act 4 Side Quest
Start Location: Upper City of Lost Souls
Quest Location: Lower Daemon Camp/Vale of Mourning
Objective: Speak with Pylades and Keuthonymos then obtain the Daemon Scroll and return it to Keuthonymos
An Inside Source Side Quest begins by speaking with Callicrates in the Upper City of Lost Souls, a town in Act 4, after you have completed the An Invitation Side Quest. You can pick this quest up immediately after you complete An Invitation so you may have missed it the first time if you only talked with him once to turn in the previous quest.
The first part of this quest will have you speak with Pylades, another ghost found in the Upper City of Lost Souls. He's found in the northeastern most portion of this town standing in front of one of the jail cells. The screenshot below will show you the map location of Pylades if you're having trouble finding him.
After speaking with Pylades you'll need to go to the Lower Daemon Camp and speak with Keuthonymos there. He's found at the border of the Lower Daemon Camp and The Salt Flats, the exact location of Keuthonymos is shown in my screenshot above. Keuthonymos is a daemon enemy which is friendly to you - a screenshot of who you're looking for is shown at the top of this guide.
Once you've spoken with Keuthonymos and updated your quest you'll need to go far to the east on the border of the Upper Daemon Camp and Vale of Mourning. Here you'll find a named daemon, Envoy Kor-Lhrut roaming around. Defeat him and loot the Daemon Scroll he drops. You'll need to return this item to Keuthonymos in order to complete the quest.
If you're having trouble locating Envoy Kor-Lhrut I recommend you use my map location below. This will show you the location of both Keuthonymos as well as Envoy Kor-Lhrut.
Envoy Kor-Lhrut who holds the Daemon Scroll in Vale of Mourning.
Map locations of Keuthonymos and Envoy Kor-Lhrut who drops the Daemon Scroll.