Quest giver is the Troll Shadowknight Treskar in Grobb. He asks for three Black Shadow Tunics from Oggok Shadowknights and two gold pieces.
After turning in he gave me this line:
"Trekar says, 'You showed dem Greenbloods! Gud werk! Here take this bag of shinies!'"
And he gave me an empty NO DROP "Backpack*", that is just a regular backpack but with a star on the end.
Also text of something like: You can't put a bag inside a bag.
My inventory slots were full, and the bag was on my cursor.
After some digging, it seems I've found the correct reward: Mid-tier Bronze Weapons.
See here:
https://web.archive.org/web/20010627...eenbloods.html
Also found this text:
"One of Hukulks chief lieutenants in Nightkeep wants you to prove your worth by returning a Black Shadow Tunic from the Greenblood Shadowknights. In fact, he really wants three such tunics PLUS 2 gold. He says he will open the coffers of nightkeep and pay you a reward. This is the shadowkinght guild in Oggok. You can get the tunic through a quest in Oggok. You will get xp, some gold, and a minor item(Bronze weapon). (Updated by Bludbaz) "