The closing credits give special thanks to Michael Ende, the writer of the original novel. Ende died in 1995, 25 years before this movie.
All letters that were shown in the movie are taken straight from the original book. However they were shortened for the movie. The letter about Jim's origin tells in the book that 32 generations were over since this and when the last members of Jim's family went down with their ship.
The movie is dedicated in memory to Rainer Gansel (12th September 1944-27th March 2019), the father of director Dennis Gansel.
Jim, who is black, discovers he is a descendant of one of the Magi, the Three Wise Men who brought gifts to the Baby Jesus. The film identifies him as descending from Casper (Kaspar), described as the only black Magus. However, in Spanish tradition, the black king is Balthazar (Baltasar), not Casper, so the Spanish dubbing adapts the dialogue to refer to Balthazar, although the document shown in the film still mentions Kaspar in written form.