For what reason did the producers and writers decide to introduce Deathstroke (Manu Bennett) in Arrow season 1? The first season of the series that started the CW's Arrowverse unsurprisingly used numerous characters associated with Green Arrow in the comics, but the inclusion of Deathstroke — the Teen Titans' biggest villain — was a bit unexpected. Deathstroke became a recurring character throughout Arrow; however, he was never a part of the show's original plan. In fact, Deathstroke's inclusion actually began with an idea for a DC Comics Easter egg.

The Arrowverse version of Slade Wilson first appeared in season 1, episode 13, titled "Betrayal," as a character who Oliver (Stephen Amell) encountered on Lian Yu. The two were forced to work together for a while, with Deathstroke taking it upon himself to teach Oliver how to fight. The two formed a bond that was broken by Shado's death and Wilson being infected with Mirakuru. In season 2, Slade Wilson moved up from a flashback character to the season's main antagonist. Following his defeat, he was imprisoned in Lian Yu, but was eventually released once Oliver decided that he could be trusted again. Deathstroke would tend to disappear for lengths at a time, but he did have guest appearances in seasons 3, 5, and 6.

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As it turns out, Deathstroke wasn't part of the original plan for the CW series. Arrow co-creator Marc Guggenheim has explained in the past that it all started when they were putting together the Arrow pilot. A scene on Lian Yu in the episode teased Slade Wilson by showing the Deathstroke mask with an arrow through it. Guggenheim said that pilot director David Nutter was looking for something to fit into this scene, and that was when Geoff Johns (who co-wrote the pilot) suggested that they use Deathstroke's mask [via EW]. After it was agreed to use the mask as a fun DC Comics Easter egg, the idea grew from there.

According to Guggenheim, many Arrow characters were unexpected additions to the show that they didn't anticipate using. For instance, Guggenheim has said that Roy Harper and Huntress weren't planned for season 1, but both characters made it in anyway, due in part to the idea that if they saved characters and stories for later seasons, they may never have a chance to use them at all. In the case of Deathstroke in particular, it's interesting to note that what was once just an Easter egg evolved into one of the Arrowverse's most memorable characters.

The introduction of Deathstroke led to several key events that had a big impact on Oliver's story in Arrow. In season 2, Slade Wilson solidified his status as one of Oliver's greatest enemies the moment he murdered Moira (Susanna Thompson). Years later, Oliver took a big step in his character development by showing that he could forgive Deathstroke for what he had done, given the circumstances. The two certainly had an interesting relationship, and though Deathstroke was one of the only main characters who didn't make it to Oliver's funeral in the series finale, there's no denying the importance of his role in Oliver's journey.

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