The Return

S3 E14: Malcolm puts Oliver and Thea in a dangerous situation that lands them on Lian Yu with Oliver's former enemy Deathstroke (guest star Manu Bennett). A flashback reveals when Oliver and Maseo returned to Starling City to retrieve the Omega bio weapon and despite being under strict orders from Amanda Waller (guest star Cynthia Addai-Robinson) not to reveal himself to anyone Oliver looks in on his family Laurel and best friend Tommy Merlyn.