We are all head over heels about Stephen Amell making his grand return to the Arrowverse in the final season of 'The Flash', and once again dawning the green hood. It surely came as a surprise to many including myself, because currently in the Arrowverse, Oliver Queen has still sacrificed himself to create 'Earth Prime' as 'The Spectre'.
After doing some hard thinking following the news, I have discovered different ways how the show can bring him back, hopefully with the explanation being anything but nonsensical.
1. Barry Time-Travels... Again!
Barry Allen interfering with the timeline, again and again, has always led to further implications (good or bad) within the lives of his friends and family. However, what if it allowed him to see an old friend?
While there is not a lot of news to base this theory on, Barry will most likely do what he does best, that being time travel this season.
Amell's return as The Green Arrow has been described as Barry and Oliver joining forces once again, for one final team up. Obviously, there is no possible way in the present day of 'The Flash' where Oliver can exist. That does not mean Barry would be unable to go back in time before Oliver's sacrifice in the new timeline, being that the events of 'Arrow' still existed, including all the crossovers with Barry.
Or, just like in Episode 22 of Season 3, Barry went back in time before Leonard Snart made his sacrifice with the Legends, to bring him back to the present, and assist him on a mission.
Time travel surely seems like a reliable, if not the most logical way of bringing back Oliver Queen one more time.
2. Multiverse?
The multiverse supposedly does still exist, with Barry and his team still having not rediscovered it yet. I know it still exists, because of other shows like 'Stargirl', and 'Superman and Lois'.
While I have not yet gotten around to watching either of them yet, I know that both shows reside on a different earth. It was made clear to me in the finale of 'Superman and Lois' past season, is that all Arrowverse shows take place on Earth-Prime, while S&L live on a different earth.
Different earths, different doppelgangers of Oliver Queen. Doing this would allow the show to rediscover the multiverse, and bring back Oliver Queen in a way that would make sense, with the only coincidence being that on his earth he still knows that version of Barry Allen, and they are both superheroes.
Who knows? Maybe if they use the earth that Superman and Lois are from, it can be a team-up of Green Arrow, The Flash, and Superman.