Darlene seems to play a key part in Elliot's "awakening" in the finale. She arrives at the hospital and, when Elliot confesses the truth about his identities, she admits that she knew all along that he wasn't the same person she'd grown up with, but she hadn't know how to handle the trauma and ran away instead.
Near the end, though, it's Darlene who reassures Elliot that all of this world is real, even if his identity is more complicated than real vs. not real: "I was there with you through all of it: fsociety, our hack on E Corp, Five/Nine, you going to prison, the cyber bombings, us robbing those evil motherfuckers after what they did to Angela. Angela, she's gone. Same with Romero, Trenton, Mobley, Shayla. Elliot, I wouldn't lie to you: this isn't in your head. This is real." Darlene even gets the last line of the series, walking into his room and repeating the show's first line: "Hello, Elliot."
