Arrow has introduced some pretty epic villains over the years, but perhaps none have been so terrifyingly awesome as Deathstroke. Slade Wilson attacked Oliver on all fronts during Season 2, ranging from his family to his city to his lady love. Oliver's decision to spare his life has meant that Slade remains a threat to this day. Unfortunately, Slade has been MIA from Arrow since Season 3, but it looks like we'll be getting Deathstroke back in some form or another for Season 5. Stephen Amell posted this to tease Deathstroke's return to Arrow:
Stephen Amell has been posting pictures on his Twitter account recently to give fans a taste of what to expect in Arrow's upcoming milestone 100th episode. Amell shared a photo earlier today that showed him and co-star David Ramsay with their arms around an imposing figure. The mystery man's features were blotted out with green, but it was clear that he's a big guy. Given that Amell is wearing the same shirt and pants in the mystery picture that he's wearing in the Deathstroke picture, we can guess that Oliver and Diggle may be interacting with Deathstroke in Episode 100.
The big question now is which incarnation of Deathstroke will be showing up in Season 5. The mystery man in Stephen Amell's photo is big enough that he could easily be Slade Wilson. Slade got a cameo of sorts in Season 4, but that appearance was nothing more than a hallucination of Oliver's as he was in the middle of a crash course in magic. There's a chance that Deathstroke in Season 5 could be another hallucination or even a dream, since we haven't heard that Manu Bennett is back on set to reprise the role of Slade; a non-speaking hallucination could enable Arrow to bring back Slade as Deathstroke without actually needing Bennett. He's spoken out about his disappointment in the treatment of Slade's character, so Arrow may not want him back on board.
A non-Slade version of Deathstroke showed up in the Star City episode of Legends of Tomorrow when Slade's son took on the supervillain mantle. Grant WIlson was significantly smaller than Slade, however, and he wore a black mask rather than the traditional two-tone Deathstroke mask, so we can probably rule out Grant as the Deathstroke set to appear in Arrow's 100th episode.
A third option for the return of Deathstroke has everything to do with the timing of the 100th installment. Arrow's milestone episode will actually be part of the big Flarrow-verse crossover extravaganza that introduces Supergirl to the Flash and Arrow universe. We don't yet know exactly how Supergirl will make her way to Earth-1, so it's entirely possible that the crossover will see some of the heroes stop over in other Earths. Season 5's Deathstroke could be the Deathstroke of Earth-2 or -3 or -4. A different Earth would certainly help explain how Robert Queen will be alive for the crossover when he's been long dead on Earth-1.
Personally, I'd put my money at this point on Season 5's Deathstroke being the Deathstroke of another Earth. I would love it if Manu Bennett came back as Earth-1 Slade Wilson to pay off on his Season 3 threat to go after Felicity to continue destroying Oliver, but the odds aren't too great on Bennett making a return. Another hallucination could be a let down after the fake-out in Season 4, so an alternate Earth version of Deathstroke could be the perfect way for Arrow to pay respects to an important villain for its 100th ep.
Only time will tell how and why Deathstroke shows up in Arrow. Check out our breakdown of what we know so far about what's next in store for Arrow, and don't forget to tune in to The CW on October 5 at 8 p.m. ET to catch the Season 5 premiere.