If you want to know exactly what happened between the explosive ending of Arrow season five and the upcoming premiere of season six on October 12th, you're going to have to sit down and read about it. Executive producer Marc Guggenheim recently confirmed a listing on Amazon.com for a new novel, Arrow: Fatal Legacies written by Guggenheim and James R. Tuck. The listing reads:
"The untold story bridging between ARROW seasons 5 and 6, exclusive to this novel! In the devastating aftermath of season five, Team Arrow must resume their mission to protect Star City. Those who have survived Chase's trap on Lian Yu discover that his plans did not end there. If his legacies aren't stopped, countless more will die. Co-authored by Arrow series producer Marc Guggenheim and James R. Tuck (Robin Hood: Mark of the Black Arrow)."
Yes, the got a guy who writes novels about Robin Hood to co-author a book for Arrow. This will be the third Arrow novel from Titan Books with the first two being Arrow: Vengeance by Oscar Balderrama and Lauren Certo, and Arrow: A Generation of Vipers by Clay Griffith and Susan Griffith.
They've done this with the comics before, having a Flash: Season Zero and an Arrow: Season 2.5, which are both considered cannon but not necessary to understanding the overall television series.
Two interesting things of note. First, from the listing above, seems that Adrian Chase had even more back-up plans. The guy must've been brutal at chess. And the second thing, according to Guggenheim's twitter, the Vigilante will also appear in the series. Producers have indicated that we'll get more of Vigilante in season six, and that when the person under the mask is revealed, it will be someone we know. But will the Vigilante's identity still be a mystery when the book is published in January 2018?