| The Shark Men | The Shark Men | Les hommes requins |
They are taken to Neryopolis, an independent state which the Shark Men invaded and now occupy. Under their leader, the Duke, Neryopolis has been renamed Squalopolis and the people rounded up and forced to wear behaviour-control lockets.
The few people of Neryopolis who have yet to wear the locket believe that their King, Nerayus, is dead, however Ulysses finds Nerayus and together they set about destroying the Shark Men's locket-control office. With the locket-control office destroyed the people are free and the Shark Men's occupation of Neryopolis swiftly ends.
Another of the Shark Men's targets was Istria, a base situated on the rings of a large planet. The occupation was short-lived however as the people of Istria fought off the Shark Men's slavery and won their freedom again. Having lost Istria, the Shark Men turned their attention to Lemnos, a companion base also built on the planet's rings, but located on the other side of the planet. The Shark Men invaded Lemnos, encountered little resistance, and swiftly installed production facilities for the manufacture of Tridents. The Shark Men used some of the Tridents to destroy Istria.
Ulysses's second run-in with the Shark Men occurs in Rebellion on Lemnos. Once again Ulysses intercepts a ship in distress. The pilot, Hipsipile, explains the situation and the two of them land on Lemnos just before the Shark Men are due to arrive and pick up a consignment of newly-manufactured Tridents.
Together they devise a plan to lure the Shark Men into a trap. The people of Lemnos, though initially sceptical and fighting among themselves, agree and work together to ensure the plan's successful execution. The Shark Men are lured into the Trident factory and locked in a room. The factory is then detached from the base and sent hurtling into the planet's atmosphere, freeing the people of Lemnos.