How to Keep Readers Guessing

In mystery novels, often it is not what you say but what you don’t say that keeps readers guessing.  From a graphic novel perspective, it is both what you don’t say and what you don’t show.  For example the Epilogue at the end of each Rock Roads saga features a character known only as “Patron,” a Spanish word that can be variously translated as boss, owner, master, or sponsor. Whoever or whatever Patron is remains largely unknown, except for the fact that he is very powerful, has international connections, and is a sinister character.  Dialog is primarily limited to gruff orders given to his minion El Cuchillo and Cuchillo’s response. However, recently there has been brief conversation with what apparently is an agent in the City, Rollo Dyce.  How or why Dyce has entered the picture is another unknown.  The only visible thing shown of Patron is his hands.  The story line indicates his residence is in a very rich residence in Rio. Many questions arise. Why is this Spanish speaking person living in Brazil and why is he not speaking Portuguese?  He seems to control some sort of organization; but what is it? Obviously he is a recurring feature.  He knows about Rocky Roads, but Rocky has no knowledge of him whatsoever. Is direct conflict with Rocky inevitable? Rollo Dyce seems to be a minor player.  What will his role be in the future?  There are a number of questions here and no immediate answers.