Isle of the dead - Roger Zelazny

ISLE OF THE DEAD
Centuries in the future, Francis Sandow is the only man alive who was born as long ago as the 20th century... who is also a god. No, not a god of Earth, but one of the panetheon of the alien Pei'ans: he is Shimbo of Darktree, Shrugger of Thunders. And the time comes when Sandow must face the most dangerous antagonist in the universe: another Pei'an god - Shimbo's own enemy, Belion.
EYE OF THE CAT
William Blackhorse Singer, the last Najavo on a future Earth, is called upon t aid in protecting an alien diplomat from a powerful and hostile member of his own species. With the aid of a shape-shifting alien known as 'Cat,' he carries out the mission, with one condition: when the mission is over, Cat wants a return bout with the man who captured him, a chase with Singer as the hunted instead of the hunter...