I don't know for sure, but there could be a powerful vampire leader who is leading one side of the war. And perhaps a young vampire who is just coming to terms with his new existence and gets caught up in the war.
In the 'v wars novel', one of the main characters could be a vampire who has been in hiding for a long time but is forced to come out due to the war. This vampire might have some unique abilities that make him a target. There could also be a group of young vampires who are rebelling against the old vampire order and are a major part of the war. And perhaps a human - vampire hybrid who is trying to bridge the gap between the two species and stop the war. Their journey and the relationships they form with other characters would be central to the story.
There could be a group of rebels in the 'v wars graphic novel'. They might be the main characters who are fighting against an oppressive regime or force. Or perhaps there is a young character who discovers some secrets about the 'v' aspect of the war and becomes central to the story, trying to bring peace or justice.
There's Luther Swann. He's a key character who gets caught up in the vampire war. He has to deal with the chaos that the vampire situation brings to his world.
Often in war novels like 'the wars novel', there could be a commanding officer as one of the main characters. This person is responsible for leading the troops and making tough decisions. There might also be a civilian caught in the middle of the war, whose life is completely turned upside down by the conflict.
Ahsoka Tano is also a main character. She is Anakin's Padawan and has her own adventures and growth throughout the Clone Wars. Another important character is Obi - Wan Kenobi. He is a wise Jedi Master and is involved in many of the battles and diplomatic efforts during the war.
In the Star Wars The Clone Wars Novel, the main characters include Anakin Skywalker, who is on his path to becoming Darth Vader. His master, Obi - Wan Kenobi, is there to guide him, or at least try to. Then there are the clone troopers. They are not just faceless soldiers but have their own personalities. Captain Rex is a great example. On the other side, Dooku is a major character. He is the leader of the Separatist Alliance and a Sith Lord. His actions drive much of the conflict in the novel.
In the 'Amory Wars' novel, Claudio Kilgannon is a central character. He is a young man who finds himself thrust into the middle of the conflict. Another main character is Ambellina. She has her own unique abilities and is involved in many of the key events. And then there's Wilhelm Ryan, who is sort of the antagonist, causing a lot of the chaos and war in the story.
I don't know for sure since I haven't read it. But it could have characters like powerful celestial beings such as archangels or star gods.
Since it's a novel about sniper wars, the main characters are likely to be snipers. They might be experienced veterans or young recruits trying to prove themselves. There could also be commanders or support personnel who play important roles in the story, guiding the snipers or providing them with necessary equipment and intelligence.
I'm not entirely sure about all the main characters in the 'Library Wars Novel' without more specific information, but usually there would be librarians who are at the forefront of the fight to protect the library.
Rey is one of the main characters. She's a strong - willed scavenger with a mysterious past and a growing connection to the Force. Finn, a former stormtrooper, is another main character. His decision to defect from the First Order has a big impact on the story.