Billy is a bandit in the Lonely Peaks, the area north of Nashkel's carnival. He is part of Ioin Gallchobhair's gang, along with Dribben. They demand a "toll" from Gorion's Ward for passing through the area. Although it is not phrased as a "your money or your life" threat, that is what it amounts to.

Billy has 5 Arrows +1 which he will use, unless you engage him in melee quickly. The amount he drops of these, as well as for his 40 regular arrows, depends on how many shots he will launch at you.