Either way, fans of Arrow who miss seeing both Laurel and Cassidy on the show will likely be excited for her return.
Additionally, it’s unclear if Black Siren is appearing on Arrow as a one-off villain for the winter premiere, or for a somewhat longer character arc.
All these story threads, along with the return of Cassidy as some version of Laurel, should make for an exciting winter premiere of Arrow season 5.
Last viewers saw of Black Siren, she was knocked out by the device meant to affect Earth-2 metas and locked up in the S.T.A.R. Labs particle accelerator pipeline along with other evil metahumans.