Zeus is the supreme overlord of Olympus. When Ulysses killed
the Cyclops, its followers appealed to Zeus on behalf of Poseidon
for revenge. Revenge was swift and severe: Ulysses's companions
were put into suspended animation until such times as Ulysses could
find the Kingdom of Hades. At each step of Ulysses's journey through Olympus
Zeus used whatever cunning trickery he could to thwart Ulysses, more
for his own amusement than out of any sense of just punishment. Zeus
thinks nothing of using other people in order to have his fun with Ulysses.
In The Black Sphere, Zeus promises to restore the sight of Heratos
if he gives Ulysses a map encoded with the route to the Graveyard of Wrecks
and Hulks instead of the route to the Galactic Glaciers as Ulysses believes.
In Calypso Zeus threatens to destroy Calypso's Crystal Planet if she
does not kill Ulysses, knowing full well that Calypso will fall in love with
him and be faced with an impossible choice.
It is fair to say that Zeus is a nasty piece of work who will manipulate anyone
he wants in order to punish those he thinks have crossed him.