'DC's Legends of Tomorrow' is set to air its fourth season beginning October 22 and has announced that they have added two significant members to the cast in the form of Ramona Young and Tom Wilson. The announcement was made on Saturday, July 21st, at the show's San Diego Comic-Con panel session.

Young (Blockers, Santa Clarita Diet, and The Real O'Neals) will be joining the cast in the series in the regular role of Alaska Yu. Described as "a typical twentysomething easily swept up by romantic notions and fantasy novels," Yu is supposedly an expert in the world of magical creatures that the Legends will encounter in season four. As she becomes an accepted member of the group, "she soon learns to her head out of the clouds to become a kickass superhero."

Comedian Tom Wilson, best known for playing Biff Tannen and Buford 'Mad Dog' Tannen in the Back to the Future trilogy, has been cast in the recurring role of Hank Heywood, Nate Heywood/Steel's (Nick Zano) father. Having served a lifetime in the military and Department of Defense, Hank is said to be in a long line of Heywoods to serve the country. Described as "charming and charismatic," he's ensured Nate has big shoes to fill.

'Legends of Tomorrow' began with Time Master Rip Hunter (Arthur Darvill) going rogue after Vandal Savage (Casper Crump) murders his family. Intending to stop Savage, Hunter recruits a team consisting of Ray Palmer/ Atom, Sara Lance/White Canary, Martin Stein and Jefferson 'Jax' Jackson, who combine to form the hero Firestorm, Kendra Saunders/Hawkgirl, Carter Hall/Hawkman, Leonard Snart/Captain Cold, and Mick Rory/Heat Wave — The Legends of Tomorrow.

Season two saw the team cope with Rip's absence after his disappearance and their fight against the Legion of Doom, the time-traveling team led by Reverse Flash (Eobard Thawne). Joined by Amaya Jiwe/Vixen and Nate Heywood's Steel, they work to stop the legion and the alternate versions of Damien Darhk, Malcolm Merlyn, and Snart from laying their hands on the Biblical Spear of Destiny, with which they can alter their fates. 

The final episode of season 3 saw the demon Mallus demand that the legends hand over the six totems and a returning Hunter sacrifice himself to allow the team to make their escape. They eventually combine the power of the totems to defeat Mallus but have their well-deserved vacation interrupted when John Constantine delivers some bad news. The Legends are informed that Mallus was not the only demon released and that they will now have to tackle magical creatures called 'Fugitives' that could prove to be a much bigger problem.

A synopsis released by CW for season 4 followed up on the events after Constantine delivers the news, reading, "As the Time Bureau is distrustful of and ill-equipped to deal with magic, the Legends must team up with everyone’s favorite demonologist to set history back on track.

"Sara and Constantine are joined by compassionate inventor Ray Palmer, hotheaded ex-con Mick Rory, rebellious totem-bearer Zari, and heartbroken historian-turned-superhero Nate as they set out to save the world – and their legacy. It’s the familiar fun of the Legends time-travelling across historical events and encountering famous figures with an added shot of magical craziness!"