|Season 4, Episode 11|
|Episode Guide Transcript|
Acknowledgement of Service is the eleventh episode of Arrow Season 4 and the 80th episode overall.
THE CHANGE THAT COMES WITH WAR- Diggle finds himself at a crossroads when he discovers one of the men in his unit back in Afghanistan, whom he helped rehabilitate, has since become a freelance hitman under the codename "Axis". Oliver approaches ARGUS commander Steve Trevor with a life-changing deal. Nyssa covers for Laurel as the eldest Lance sister looks for Sara, eventually joining Diggle in his quest for answers and justice. Malcolm tends to a recovering Thea despite her protests.
- Stephen Amell as Oliver Queen
- Katie Cassidy as Laurel Lance/Black Canary
- David Ramsey as John Diggle
- Willa Holland as Thea Queen
- Katrina Law as Nyssa al Ghul
- Caity Lotz as Sara Lance (flashbacks)
- Colin Donnell as Tommy Merlyn (credit only)
- and John Barrowman as Malcolm Merlyn
- Christopher Meloni as Maxwell Lord
- Richard Armitage as Steve Trevor
- Sam Claflin as Richard Rienhardt/Axis
- Jacqueline Emerson as Olivia Baxtor
- with Arthur Darvill as Rip Hunter
- and Marc Alaimo as Theodore Gaynor
- Antagonist: Richard Rienhardt
- Tommy does not appear in this episode. Sara only appears in flashbacks.