Mattis is a character in the book Ronja Rövardotter, by Swedish author Astrid Lindgren. Mattis is Ronjas dad and robber chieftain. He lives with robbers, his wife and daughter Ronja Lovis in a large castle that has been divided by a lightning strike. He is a person with strong emotions, he was bubbling with happiness and pride when Ronja born, when he is angry he throws things around him and he becomes fully enraged when Ronja befriends the son of his worst enemy, Borka. In the film version portrayed by actor Börje Ahlstedt.
I liked that Mattis character best!