|Season 4, Episode 9|
My Demons is the ninth episode of Arrow Season 4 and the 78th episode overall.
POISONOUS FRIENDS- Thea gives solo heroics a try and comes across an escaped Werner Zytle, becoming exposed to a new variant of Vertigo in the process. Diggle meets with Thea's future roommates and discovers an awful secret. Nyssa kidnaps and tortures Malcolm for information. Elsewhere, Laurel learns more about the "Dark Canary" in her dreams.
- Stephen Amell as Oliver Queen
- Katie Cassidy as Laurel Lance/Laurel Lance (Earth 2)
- David Ramsey as John Diggle
- Willa Holland as Thea Queen
- Katrina Law as Nyssa al Ghul
- Caity Lotz as Sara Lance (hallucinations)
- Colin Donnell as Tommy Merlyn
- Audrey Marie Anderson as Lyla Diggle
- Deborah Ann Woll as Andrea Beaumont
- Bex Taylor-Klaus as Cindy
- and John Barrowman as Malcolm Merlyn
Special Appearance ByEdit
- Stephen Lang as Damien Darhk
- Peter Stormare as Werner Zytle/Count Vertigo
- Rachel Skarsten as Talia al Ghul (Earth-3) (flashbacks)
- Maiara Walsh as Penny Tate
- and Josh Lucas as Kyle Abbot/The Wolf
- Antagonist: Werner Zytle
- First midseason premiere to not feature Quentin and the second to not feature Felicity.
- First appearance of Rachel Skarsten as the Talia al Ghul of Earth-3. The Earth-1 version of the character previously appeared as a child in the Legends of Tomorrow episode titled Left Behind.
- 3rd and final appearance of Zytle.