Rift Quest:Tumbling Down  

Down the east ramp from the platform you are on is a cave with several crystals and deactivated machines.

Go in and left to the first crystal with a robot next to it. Click on the Crystal to activate Dalvio's soul into the mechanical. Go to the middle of the room and destabilize the power source to draw out Lexannus. Kill him and he will transfer into the robot on the power source as an Elite. It is not as bad as it looks but it is gonna be a rough fight. Once Lexannus' second life is ended, return to Senelei Redrel.