Season 4 (The Flash: 2014)

"My name is Barry Allen, and I am the fastest man alive. To the outside world, I am an ordinary forensic scientist. But secretly, with the help of my friends at S.T.A.R. Labs, I fight crime and find other metahumans like me. But I became lost in time. It took everything in my friends' power to bring me back. And in doing so, our world was opened up to new threats, and I'm the only one fast enough to stop them. I am The Flash."

- Introduction

The fourth season of premiered on October 10, 2017, on The CW and concluded on May 22, 2018. The season consisted of 23 total episodes during its run.

Synopsis
Running up against an evil time remnant version of yourself is something no one should ever have to do, but that's exactly what faced Barry Allen (aka The Flash) as he fought to save the life of fiancée Iris West from the God of Speed known as Savitar.

Barry's victory was short-lived, however, as an unbalanced Speed Force began to wreak havoc on Central City, forcing Barry to sacrifice himself for the greater good.

With The Fastest Man Alive now trapped inside an extra-dimensional energy, and unknown dangers lurking in the shadows, it will be up to Team Flash to free Barry from his own personal Hell.

Main Cast

 * Grant Gustin as The Flash (Barry Allen)
 * Candice Patton as Iris West-Allen
 * Danielle Panabaker as Killer Frost (Caitlin Snow)
 * Carlos Valdes as Vibe (Cisco Ramon)
 * Keiynan Lonsdale as Kid Flash (Wally West) *
 * Neil Sandilands as Thinker (Clifford DeVoe)
 * Tom Cavanagh as Harry Wells / Harrison Wolfgang Wells / H. Lothario Wells / Wells 2.0 / Wells the Grey / Reverse-Flash/Harrison Wells (Eobard Thawne) / Sonny Wells / H.P. Wells
 * Jesse L. Martin as Joe West

Recurring Cast

 * Katee Sackhoff as Amunet Black (Leslie Jocoy)
 * Danny Trejo as Breacher (Josh)

In-Universe Guest Stars

 * Emily Bett Rickards as Felicity Smoak / Felicity Smoak
 * Stephen Amell as Green Arrow (Oliver Queen) / Dark Arrow (Oliver)
 * Victor Garber as Firestorm (Martin Stein)
 * Caity Lotz as White Canary (Sara Lance)
 * Chyler Leigh as Alex Danvers
 * Franz Drameh as Firestorm (Jefferson Jackson)
 * Paul Blackthorne as Quentin Lance
 * Jeremy Jordan as Winn Schott
 * Juliana Harkavy as Black Canary (Dinah Drake)
 * Melissa Benoist as Supergirl (Kara Danvers) / Overgirl (Kara)
 * David Ramsey as John Diggle / Thinker/John Diggle (Clifford DeVoe)
 * Wentworth Miller as Citizen Cold (Leo Snart)
 * Russell Tovey as The Ray (Ray Terrill)
 * Frederick Schmidt as Metallo-X
 * Katie Cassidy as Siren-X (Laurel Lance)

Notes:
 * 1) Keiynan Lonsdale is credited as a series regular through 4x03  and a special guest star in.