When Slade says to Oliver that it will be "like old times", the title sequence from season one appears as opposed to the one from season five.
This is the highest rated episode of the series and the highest rated episode across the whole Arrowverse.
In exchange for his help in stopping Chase, Oliver offers Slade information on the whereabouts of his son. Grant Wilson appears in the DC's Legends of Tomorrow (2016) episode "Star City 2046 (2016)" and, rather than his comic book moniker The Ravager, has taken on his father's mantle as Deathstroke.
In early April 2017, Stephen Amell and Marc Guggenheim posted on social media that Manu Bennett would be returning as Deathstroke, including images of the masked character appearing on set. Bennett posted replies stating that he was not returning for Arrow because he was filming his own series, "Shannara" in Auckland, New Zealand.. Guggenheim later posted that fans would be "hearing the voice" of Bennett as Deathstroke, implying that a body double wearing Deathstroke's mask would be used for filming, with Bennett providing only the voice of the character.