Riff knew him, well, of him if his assumptions were correct. Unlike Lower-Plate, when people died in Upper-Plate it mattered. The doctors had been first but the killer had been branching out since then. The news hadn't reported the specifics on how the targets were dying but there had been idle gossip of deaths occurring with the slash of a sword or how the damage looked more like poisoning than being sliced up.
Riff found the potential behind that concept fascinating so he'd gone looking. How no one had taken care to notice him before wasn't unsurprising: Upper-Plate residents had a selective view of the world, after all.
Even if the man in question carried a sword at his side.
Riff had simply observed him before but he had a feeling that tonight was going to be a strike night. So when the man entered the plaza, Riff was waiting on one of the stone benches. Riff called out, genially,
"Excuse me, sir? Isn't it a little late for a stroll?"