“Who Are You?” sees the return of Katie Cassidy to the show as Black Siren. Around 17 minutes into the episode, she has a meeting alone with Oliver at night. The team, however, doesn’t trust her and snuck along to eavesdrop on their little rendezvous. When she reaches into her jacket, they freak out and attack causing a fight to break out. Oliver quickly ends it by throwing a tranq dart into her shoulder which instantly incapacitates her. She later awakes in a cage. Around 35 minutes in, she gets punched out by Felicity (Emily Bett Rickards).