He is invulnerable by stages. You battle him to his minimum, battle him some more, etc... Each time his attack routines change, with an occassional comment thrown in. It was done this way to prevent the "Finger of God" cheat and to make it more challenging.

thats cool.. but when i'm fighting him, his health never resets.

edit: i'm stupid. i beat him. thanks for the help. now i can get on with the bussiness of rescuing imoen *eg*

For some reason, big M is invincible to me. i dont mean figuratively. i tried to cheat kill him. he takes damage (i use restore to remove his protection sphere) but the jerk wont die. i even edited with shadowkeeper and tried rapture of the father. is there something i need to do before entering his prison plane? please help