- "Terrible it is, how easy it is to bribe city officials..."
- —Sly Harold to Rodney.
Harold is a close friend and partner of Dapper Rodney. Of a philosophical bent, he often discusses criminal actions and the illegal activities of dishonest city officials with Rodney. He seems to be of some importance in the Roaring Boys and is able to order others about without having to do much of the heavy work.
The Wyrmwood Deceit
Sly Harold operates out of the Old Port District, and along with Rodney helps run the affairs of the Roaring Boys working in that area. He helps defend the dock area when Corvo Attano and members of the City Watch interfere with the operations of his gang.
Harold and the rest of the rest of the Roaring Boys search unsuccessfully the Wrenhaven River with Broken Tom for Corvo Attano. Later on, he tries with Rodney to jump Watch Officer Cottings whose investigations lead her closer to the source of the contraband weapons, only to be ambushed by her.
- Sly Harold holds a whistle capable of summoning the Big Lad and uses it when his gang is hard-pressed in a fight, often at the urging of Rodney.
- In deference to his position, other Roaring Boys sometimes call him "Mister Harold".
Characters in Dishonored: The Wyrmwood Deceit