The new book "Revan" says the emperor is a young smith who used a ritual to suck ALL life and force off of the planet he was on and into his own body. This gave him immortality. It also suggests these souls are trapped inside him. The planet now is a null zone in the force. There is no life, no force, and even the light is dimmer than normal as an after affect.
The new book is total crap.
It was penned by a hack writer who never even knew about KOTOR until they cut him a check. He plays fast and lose with the facts and changes the plot of KOTOR (yes changes it) to fit his silly story.
I will strike down your heresy darthhavok, and your silly belief in Revan (the book). =)