The main character in the 'Kingdom Come Superman Graphic Novel' is Superman, but there are many others that help drive the story. Wonder Woman is one such character. She has her own ideals and often challenges Superman's way of thinking. Then there's Captain Marvel, who brings his own set of powers and moral code to the table. The interactions between these characters, along with Superman's attempts to bring back a sense of order, form the crux of the story. Additionally, minor characters like the various new superheroes and villains in this alternate world add depth and complexity to the narrative.
The main character is, of course, Superman. But there are other important characters too like Wonder Woman. She plays a significant role in the story, often being an ally or a counterpoint to Superman. Another character is Lex Luthor, who is always there as Superman's nemesis in one way or another.
In 'Kingdom Come Superman Graphic Novel', Superman is the central figure. However, there are several other characters that are integral to the story. For instance, the Flash is in it. He represents the younger generation of heroes. Batman also makes an appearance. His relationship with Superman, which has always been complex, is further explored in this graphic novel. There are also new characters created specifically for this story, who add to the overall conflict and plot development.