Since I'm not familiar with the 'on a pale horse graphic novel', it's hard to say. However, it might have a protagonist who is somehow associated with the pale horse, like a person who discovers the horse or is chosen by it. There could also be an antagonist who opposes the main character's journey or purpose related to the horse.
Often, the rider of the pale horse is a main character. But it could also include other characters that the rider interacts with, like the people in the places the rider travels through.
I don't know for sure as I haven't read it. But surely the pale queen herself is one of the main characters. There might also be some characters who serve her, like knights or advisers, or characters who are against her rule.
Well, without having read the 'on a pale horse graphic novel', it could potentially be centered around a post - apocalyptic world where a pale horse is a symbol of something significant. It might follow a hero or a group of people who encounter the pale horse and their lives are changed by it. It could also have a religious or mythological undertone, as the pale horse has significance in some religious texts.
There are soldiers. They play important roles as they interact with the horse during the war.
The pale horse and rider are the most obvious symbols. They likely represent death or a dark force approaching. It gives a sense of doom throughout the story.
Since I haven't read this particular 'dark horse aliens graphic novel', it's hard to say for sure. However, common main characters in such stories could be a brave military leader who has to defend Earth against the aliens, a curious scientist who wants to study the aliens rather than fight them, or a young person with some special ability that becomes important in the encounter with the aliens.
Liz Sherman is another important character. She has pyrokinetic abilities, which means she can control fire. She has a complex personality and a troubled past. Her relationship with Hellboy is also an important aspect of the story, as they often team up to fight against the forces of evil in the 'Dark Horse Hellboy Graphic Novel'.
Since I'm not familiar with this particular 'death rides a pale horse novel', it's difficult to say who the author is. It could be an indie author or it might be a more obscure work from a particular genre - specific publisher. There are so many novels out there that without more context, it's impossible to determine the author.
The horse is also a main character in a way. It has its own personality. In some graphic novels, the horse might be a wild mustang that the girl befriends and tries to tame. The horse could be stubborn at first but gradually forms a deep bond with the girl, like in stories where the horse helps the girl overcome her fears or achieve her goals.
Since I don't know much about the 'the pale order novel', I can't say for sure who the main characters are. But they could be leaders within the pale order, or perhaps outsiders who become involved with the pale order in some way.