For the mission Ask Halos About Comana, he can be hard to find. Players can go to The Two-Tailed Rat and wait by holding the space bar. Other times of day, he can be found in his house in the far-southwest corner of Cademia.
Halos' house features a business-like counter, a storeroom with a separate entrance (filled with poison-trapped crates), an office, and a bedroom. The bedroom has a secret room off of it, which is access by a lever underneath the southwest crate in the office room; the secret room has a ladder down into the Cademia Sewer.