Roger Zelazny 
Prince of Chaos 
The Chronicles of Amber Book 10

Upon the death of Swayvill, King of Chaos, Merlin unexpectedly finds himself under Black Watch with only two heirs between him and the throne. In his absence a deadly game of thrones has greatly reduced the number of heirs. Merlin has his suspicions about this, but before he can do more than raise voice to his questions he is once again caught up in the struggle between the Pattern in Amber and the Logrus in Chaos. A struggle that could destroy the entire multiverse. Even armed with a Spikard, Ghostwheel, and his whits it will take a miracle for Merlin to survive. An epic conclusion to one of the greatest fantasy series of all time!