I get these questions a lot so I'll try to explain it as best I can in this post. :)
For the first three comic issues, it was easy since I was turning my already existing novel into comic book format. So it was just a matter of migrating the characters and select scenes and condensing the stories into 24 plus pages each.
It was a little bit more of a challenge with coming up with the sequels. Since I had decided that the sequels were no longer going to be in novel format, I needed to continue the stories on in comic book format, thinking up new plots, scenarios, developing and expanding characters, creating new characters, and find a new and unexpected direction the story should take. The more strange and bizarre, the better.
No set formula, just inspiration:
The best way I can sum it up is this: An idea just hits me, and I go with it. I rely a lot on feeling, atmosphere, even what I eat or drink or the music I happen to be listening to. It may come one year and last for weeks, it may just last one day. Each year that the comic book was written, I look back and I can tell what inspired me.
My first inspiration: In the novel, stories 1 and 2 were were inspired by my being a "recovering Catholic" and questioning some aspects of why we believe in saviors. After I had written those, I needed to come up with story 3, which was inspired by.....
Dreams:
....My next stories were from what comes up in my dreams. Yep, dreams. Story 3 was the result of a bizarre dream I had.
And comic issues 5 and 6 were the product of some very bizarre dreams involving ancient Vampires, Catholic reliquaries and the "incorruptible bodies" of Saints. And then I started listening to more black metal music. And all these came together in a week of strange dreams. Well, you can see how my imagination started to run wild.
But not all Issues are inspired by Dreams. It's unpredictable.
Take for example, Issue 4, which was more of a character expansion, as in what had happened to a character's son or father and to develop them more. But there was still the challenge of what direction I wanted to take the character to. And it's still developing.
And more issues have yet to be written, so who knows what will inspire those?
So in short, there will be days when I don't "feel" anything, or find no inspiration, and then there are weeks when I get so inspired that I can write the entire story line in a week and keep going, thinking up new scenarios and plot lines, what's next for my characters, and create new characters.
There is no magic formula. It's just inspiration that's needed. :)