[Gothmog, Lord of Balrogs]

like Ar-Cunin said, but remember to open all the doors. Once the gas cloud is in the Ice Room, you can beat up the golem. The fire giant (next) is also tough, since you have to get his elementals to follow you into the ice room (they freeze). otherwise he regenerates. That Ice Golem thing made me really angry too, until i read some of the Library Notes...