Man in the Long Black Robe is a quest that can be done with a group when you raid the Black Claw Village with your group (the first elite spot in Aion as Asmodian. You can get it from Pandaemonium at level 15 from NPC Deyla.

Man in the Long Black Robe quest guide:

Talk with Deyla in Pandaemonium.
Talk to Zerpi.
Meet Osvi.
Speak with Annju.
Go see Neparinerk.
Talk with Banatisai.
Get the package from Black Claw Village (location on the map bellow).
Meet NPC Deyla to claim your reward (77300 XP + Deyla's Earrings).





NOTE: After you touch the evidence, you will be atacked by an elite mobb, so be carefull. After you kill him, don't forget to pick up the package. Man in the Long Black Robe quest is usually a quest that people don't know about, so share it with your group before raiding Black Claw Village.