From its pilot, Arrow set up the presence of Slade Wilson, aka Deathstroke, by having his mask appear on the island where Oliver Queen was marooned for the better part of five years. Eventually, Wilson would become a central character on the show, appearing in both the present-day and flashback segments for the series' first two seasons.
However, while Deathstroke had such a big presence in the show's early days, it turns out he was never originally supposed to appear on Arrow.
"We had no intention seeing Deathstroke or Slade Wilson in Season 1, and we saw them both," Guggenheim told Entertainment Weekly.
"David Nutter was on set [of the pilot], and he wanted basically a foreground element," the producer recalled. "He was like, ‘What can we stick here?’ and he had the idea of maybe something with an arrow through it. Geoff Johns happened to be on set and said, ‘Well, what if it’s like a mask, it’s half-black and half-orange, and it’s basically the Deathstroke mask?’ And we were like, ‘Oh, great Easter egg!’ because we were all about the Easter eggs back then."
While Wilson's time as a regular ended in Season 2, the character returned sporadically in later seasons.
Returning Tuesday, Oct. 15 at 9 p.m. ET/PT on The CW, Arrow's final season stars Stephen Amell as Oliver Queen, David Ramsey as John Diggle, Rick Gonzalez as Wild Dog, Juliana Harkavy as Black Canary, Katie Cassidy as Black Siren, Katherine McNamara as Mia Smoak, Joseph David-Jones as Connor Hawke and Ben Lewis as William Clayton-Queen.