Villeharduin

 was a member of the Blue Collar (Utility) class on a train-city on a devastated planet. His children were Guillame, Burdine and Jennette, who found Nyssa when she appeared in their compartment. At first they threatened her, but when they learned she was from off-world, they wanted her help for their rebellion. They brought Nyssa to Mr Villenarduin, who explained the train-city to her.

In reality, Mr Villeharduin and the entire train-city were part of an illusion that Maya had created for the Fifth Doctor and Nyssa. (PROSE: Confabula)