When you enter Doryani's Machinarium, there are three paths you can travel and a staircase that leads to an empty boss room. Each path has a payload you'll need to transfer and is connected to one of the boss's arms. When you reach the end of each path, you are presented with three buttons. Each button augments that arm with an element: fire, cold or lightning. After you've completed each path and you have augmented each arm, you can then fight the boss you have created. The reward you'll receive is based on the options you have chosen. 
(20-50)% increased Experience gain
Monster Level: 80
Found Items have a 10% chance to drop Corrupted in Area
Unique Boss is augmented by Player choices
We are ever the makers of our own undoing.
A simple tool to price check your items in path of exile by "copy and paste". It is that simple!
Price in Leagues