He is in the Advocate's Tower on top of the hill near the Scriveners.
Lore & Dialog
Sir Rylanan tells you, "I've recently been assigned to Holtburg to build a garrision and be on the lookout for suspicious happenings. There is one fellow on the outskirts of town that I've been keeping my eye on. He's just moved here from Marae Lassel and sometimes comes into town for provisions. He says he's been "reformed", but I can spot a bandit when I see one! Townsfolk say they've spotted shady-looking guests coming and going from his house at odd hours. Could you go check on him? His house lies to the northwest of town, past the Holtburg West Training Academy."
Sir Rylanan tells you, "You're back! How did your interview with that ex-bandit go? Did you find anything of note in his house?"
Sir Rylanan tells you, "You say you found this note in that bandit's house? Surrounded by a pack of Hollow Minions? I knew that fellow was up to no good! Look here...it refers to Asuger Temple, up to the north. Last I heard, the temple was just a Banderling hideout...harmless really. I wonder what sort of trouble might be brewing up there? Find out what is going on, and I'm sure I could find something in the Guard's coffers to reward you with."