the mystery still hasent been discovered !!!!!! its a secret passage that extends from act 1 all the way to act5 , but if u are lucky enough to find out how to open portal be very carefull becaue you will encounter monsters and goblins beyond your wildest dreams ,,,,,, but the reward if u make it to act 5 , no tp's or wp's , is awesome and thats the second secre ... remember MUMM is the word