Into The Labyrinth by Margaret Weis & Tracy Hickman (Death Gate 6)

The great machine finally works as intended. Hugh the Hand set out to fulfil a contract he never wanted equipped with a magic dagger.

Xar learns about the Seventh Gate from the undead and set outs to find it. Since Bane failed to kill Haplo, Xar decides to send his former lover and mother of his child after him.

We meet Zifnab, Aletha, Paithan, Rega, Roland in the Citadels. The Tytans are there too ofcourse.