When you travel to the epic server cluster through one of these portals for the first time it is equivalent to re-creating your character on said cluster, you start with the survival tools, fresh skills, and a new affinity. Also any premium time and coins in your bank is available to you on both servers, so using an epic portal essentially allows you to have two premium characters for the price of one. Your character on freedom doesn't disappear, meaning you can travel back to freedom whenever you wish. You will log on at the position of the portal you used to teleport to the epic cluster when going from epic to freedom and the same in reverse (the positions are saved, not the portals you used).
The portals have a 1 hour cooldown - you may not transfer back to the other server cluster in that time.
=== Notes ===