Season 4 (Arrow)

The fourth season of Arrow premiered on October 7, 2015 on The CW.

Official synopsis
''After defeating his most formidable foe to date and riding off into the sunset with longtime flame Felicity Smoak, Oliver Queen (a.k.a. The Arrow) left Starling City with the hopes of beginning a new life. But will Oliver ever truly be able to leave behind his past as the Arrow, and, if so, what becomes of the team he has worked so hard to assemble? Will Diggle, Thea, and Laurel be left to continue Oliver’s crusade without him? And with Malcolm Merlyn having ascended to the top of the League of Assassins as the new Ra's al Ghul, is anyone really safe?''

Main cast

 * Stephen Amell as Oliver Queen/Green Arrow
 * Katie Cassidy as Laurel Lance/Black Canary
 * David Ramsey as John Diggle/Spartan
 * Willa Holland as Thea Queen/Speedy
 * Emily Bett Rickards as Felicity Smoak/Overwatch
 * John Barrowman as Malcolm Merlyn/Ra's al Ghul
 * Paul Blackthorne as Captain Quentin Lance/Detective
 * Neal McDonough as Damien Darhk

Recurring cast

 * Echo Kellum as Curtis Holt
 * Elysia Rotaru as Taiana
 * Ryan Robbins as Conklin
 * Caity Lotz as Sara Lance/The Canary
 * Brandon Routh as Ray Palmer/The Atom
 * Jimmy Akingbola as Baron Reiter
 * Parker Young as Alex Davis
 * Grant Gustin as Barry Allen/The Flash
 * Eugene Byrd as Andy Diggle
 * Charlotte Ross as Donna Smoak
 * Audrey Marie Anderson as Lyla Michaels
 * Cynthia Addai-Robinson as Amanda Waller
 * Katrina Law as Nyssa al Ghul
 * Natasha Gayle as Talibah
 * Tom Amandes as Noah Kuttler/The Calculator

Confirmed plot points

 * The season's main antagonist will be Damien Darhk, introduced by name in the third season finale. He will have been operating for three months prior to the premiere.
 * The season will follow a lighter tone to that of season 3.
 * Oliver will face a criminal organization known as Shadowspire in the flashbacks, led by Baron Reiter.
 * Mari McCabe will make an appearance in the fifteenth episode.

New characters

 * Noah Kuttler: A criminal mastermind and technical genius, The Calculator — aka Noah Kuttler — uses his advanced skills in computer science and internet manipulation to blackmail Roy out of retirement to do his bidding, which leads to an epic battle with Team Arrow.