There are 2 books in the Succession series. The newest book is The Killing of Worlds which came out in 2003.

1
The Risen Empire

Book cover of The Risen Empire
The undead Emperor has ruled his mighty interstellar empire of 80 human worlds for 1600 years. Because he can grant a form of eternal life-after-death, creating an elite known as the Risen, his power is absolute. He and his sister, the Child Empress, who is eternally a little girl, are…
When you buy books, we may earn a commission that helps keep our lights on (or join the rebellion as a member).

2
The Killing of Worlds

Book cover of The Killing of Worlds
Scott Westerfeld, the acclaimed author of Fine Prey, Polymorph, and Evolution's Darling, reached new heights of excitement in last spring's The Risen Empire, and left readers begging for more. Now he comes through with the dazzling payoff in book two of Succession, The Killing of Worlds.

Captain Laurent Zai of…