What is the name of the secret society that protects the Holy Grail in "The Last Crusade"?

The secret society that protects the Holy Grail in “The Last Crusade” is the Brotherhood of the Cruciform Sword.

The group appears in Venice after Indiana Jones and Elsa Schneider uncover clues leading toward the Grail. Its members initially attack them because they believe the pair may threaten the artifact’s secrecy. Their leader, Kazim, explains the brotherhood’s purpose and reveals that Indiana’s father, Henry Jones Sr., is being held by the Nazis.

The brotherhood represents a centuries-old tradition of guarding the Grail rather than seeking to use its powers. In the film’s backstory, the Grail was protected by a knight who remained in the Temple of the Sun, while a wider organization of protectors formed around the secret. The group later attacks the Nazi convoy traveling toward the Grail, although Kazim and many members are killed.

A common mix-up is confusing this society with the Knights Templar, the real medieval military order. The film’s brotherhood is a fictional organization created for the Indiana Jones story.