The length of the Mirage story is hard to define precisely. It could be a few pages if it's a concise version or it could stretch into a full-length novel if the author decides to expand on the plot and characters.
It's hard to give an exact number as new Spawn comics are constantly being produced. But there are definitely a significant number of them over the years.
There are also some online tools available for spawning book covers. Canva, for instance, offers a variety of templates. You just need to choose a template that suits your novel's genre, customize the text with your novel's title and author name, and add any additional elements like images or graphics from their library.
First, know the 'Spawn' universe well. Read the comics, watch the movies or shows if any. Then, come up with an interesting idea for your story, like a new adventure for Spawn. Start writing, focusing on creating a good plot and interesting characters.
The Spawn comic ended with a mix of resolution and ambiguity. Some key characters had their fates sealed, but it left room for interpretation about the future of the Spawn universe.
The end of Spawn Comics was a culmination of various plot twists and turns. It wrapped up the main arcs while leaving room for interpretation and speculation among readers.