It was over ten years ago that I first started working on my Johnny Graphic stories. And since Day One, I’ve tried to populate them with ghosts that readers would find interesting and endearing. Though it took me a little while to figure out exactly how to do this, I knew I wanted my wraiths and specters to be out of the ordinary. I wanted them to touch real life in a way most fictional ghosts cannot. To steal an observation from one of my Amazon reviewers, I wanted to do for ghosts what Isaac Asimov did for robots: Make a set of consistent rules for how ghosts “lived” their lives. There are three key points.

• Ghosts may exercise their free will by serving living humans and—thus endowed by living effectuators—assume a degree of corporeality to perform the tasks requested of them in our material universe.

• Ghosts who are engaged in corporeal activity that may harm living humans or animals are subject to the same injuries as the living—though they cannot be killed a second time.

• Ghosts are free at any time to withdraw from their arrangement with living humans, but thereby lose the benefits of corporeality.

After a break of three or so years, I launched into the third Johnny book and am now about halfway through the first draft. And I’m having a great time working with my ghost characters—both regulars and new additions. In the first book Johnny and his sister are given a drawing of their missing parents, showing them being guarded by two giant ghost wolves. In the third book those two huge ice wolves take part in the action. It so happens they’re a bit inscrutable, but they’re definitely good guys at heart. I haven’t decided yet if they’re going from Okkatek Island to Zenith with Johnny and the others. (You become fond of so many characters, it’s tempting to continue their stories. But there’s never enough room to do so.)

Another ghost whose name cropped up in the second book needed to be made into a real character. He was an ancient shaman who had some association with the villain of my story. Indeed, he may have been some kind of co-conspirator. But to my surprise, when he finally appeared in the “flesh,” he wasn’t exactly what my hero, or I the author, expected. It’s a fine thing when characters surprise their creators: “No, sir, I am not like that. I am like this.” More often than not, your characters know more than you do.

Of course, my two favorite ghost characters in the series both have big roles in the final book.

I knew from the moment I invented him that Colonel Horace MacFarlane would be a central character—as the senior officer of the First Zenith Cavalry Brigade. And he’s the sort of stalwart, honest, reliable ghost you’d want on your side. An honorable military man.

The little girl ghost Bao surprised me, morphing into a key character. In fact, she has one of the few POV roles in the series—there are chapters in all three books written from her point of view. Being a child, albeit a child a thousand years old, means she is constantly learning, constantly providing a fresh outlook. She was without a family for a millennium, and now that she has one again she aims to make the most of it. And in both the first and last book her actions are vital to advancing the plots.

When I wrap up the Johnny Graphic Adventures, one of the things I need to do is deal with the fate of the ghosts. I intend to give them the option of real, final, irrevocable death—which many ghosts have long desired. But it’s going to be painful to say goodbye to some of these characters. I’m hoping that a few decide to stay with Johnny and Mel and Nina and Dame Honoria until the end.