Patricia is the heroine of our stories. She is a purple hippo, who lives with her family on Lake Victoria, near the town of Jinja at the source of the Nile. It soon becomes clear she has some special powers and can't be seen by (nearly all) the humans.
Hugo the hippo is Patricia's father. His natural instinct is to keep Patricia safe from danger, but Patricia's adventures often lead her into dangerous situations with the humans. Patricia knows little about her mother, and she also has a grandfather named Herbert.
Humphrey the monkey is Patricia's best friend. He is almost as brave as Patricia, but not as wise, so occasionally does silly things that get him into serious trouble.
Frederick the crocodile (self-proclaimed 'King of the Crocs') is very dangerous, and has a deep distrust of the humans ever since one human killed his brother. The other animals stay well clear of the crocodiles.
Beth (or Bethsheba to give her full name) is a young girl that Patricia makes friends with on the banks of Lake Victoria. It soon becomes clear that Beth is only one of very few humans who can see and communicate with Patricia.
She is also friends with Elewa, who owns a small boat that enables her to visit Patricia on Lake Victoria.
Beth lives with her mother and father, Grace and Gideon,
in Jinja. Gideon works at the construction site of the nearby Owen Falls Dam.
Professor Titus Germanicus Pompei (or simply 'the Professor') is a tall, quietly-spoken man that believes Beth's claims to have befriended a purple hippo with very special powers – even if he can't see Patricia himself.
The Professor owns an airship named the Hermes, which can easily fly the length of Lake Victoria… to the 'Sacred Place'.
Commissioner Colombo is the Head of Police in Jinja. Aided by his deputy, Wilko, he is trying to ensure everything runs smoothly as the Owen Falls Dam is constructed, but he is constantly hampered by mischevious monkeys and angry crocodiles.
Colombo has a hooked hand, which may have something to do with his deep dislike of the crocodiles!
Elmo is a hippo that belongs to the same tribe as Patricia. In one of Patricia's early adventures Elmo goes missing from the tribe after an encounter with some humans and is soon believed to have died.
In the latest books by David Jackson we learn what really happened to Elmo and get to read about his further journeys with his new found friends.
Whilst on the island of Busaka, Elmo makes friends with a fez-wearing chimpanzee named Charlie and a white leopard called Cleopatra. The antics of Charlie and his cheeky son, Houdini, soon get them into all kinds of scrapes and catch the attention of the new Police Commissioner of Jinja.