Dream World

The Dream World is a place that the time travelers go when they are not awake. It is its own world that they share, proven to be altered by their wishes. They also, often unintentionally, create inhabitants called 'Figments' based on people they had known from the real world.

History
Piper Mack revealed in the original timeline that she goes to a forest when she dreams. After the event that sent the time travelers into the past, it was soon revealed that Warren Rennie and Elias Adams also travel there. After Piper took her own life, she discovered that she was stuck in the dream permanently. It became a platform through which travelers Warren, Elias, Piper, Adam Reese, Liz Stroller, Glenn Dang, and Kylie Bricker could meet.

In 2013, it was soon revealed that Seth, who had died prior to the event that sent the travelers into the past, had been trapped there, unaging, similar to Piper's situation. His subconscious created a Figment named Brian, who was bitter and manipulative. Brian guided Seth into altering the forested dream world and creating a town, but then Brian took control of the town and created an army.

Warren, feeling overwhelming guilt for the lives he'd altered, also subconsciously created Rachel (Figment) and Eric (figment), who tormented him but also helped him in creating his own town. They found Seth, abandoned by Brian. While Warren was awake in the real world, Brian and his army attacked Warren's town. Brian convinced Rachel to take Seth's "life force" and become real herself, thus making her able to control the dream world. He then tried to do the same to Warren, but ended up trapping Warren in the dream and entering the real world in Warren's body.

In 2014, users of a popular drug called Thumper found themselves able to enter the dream world while under its influence. People like Amber and Amanda have entered the dream world through this method. Piper, at this time, was revealed to have created her own peaceful town but had been haunted by her figments before being found by Amanda.