Ok, I really don't know what happened, I completed the Veteran Maelstron Arena, this guy "Baron Moves-like-a-Smoking-Plume" appeared, I talked to him and left the place. Later I decided to do the arena again, improve my score and the portal was gone. I logged out, logged in, closed the game, opened it again, and still the same guy and no portal.
Did I do something wrong? Do I have to wait something to happen or complete any other quest? I finally completed the arena, was excited to do this and get my master weapons.
So, is it normal?