I was very surprised (and pleased) to see an update!
Thanks, Sep.
I have to say, though, that I don't understand Saes's reasons for sealing the underworld. Suppose there are 100 million people in the world, and they all live for an average of 100 years.
Then, on average, 1 million souls pass her gates every year. Now suppose Graz'zt invades, and all 100 million are killed in a year. Saes gorges on death. But next year- no souls come. None are left alive, and so none can die. No matter- she's still up by a net 99 million souls. The year after- still no souls. The year after that- nope. After 100 years she's where she would have been had there been no invasion. From that point on she is in a net famine of souls.
It is really in her interest to let some out to live again- for unless there are living people, no one can die.