Summary[]
The Frozen Forest is on the right side of the timeline, after time. When someone manages to travel forward in time, they break through the timeline and enter a forth dimensional space called the Frozen Forest. This space is outside of time, therefore a being inside of it can see all of time, and look through it like a library.
The Frozen Forest holds the physical part of reality. This and the Eternal Prison create what we experience as reality and the timeline.