Since I haven't read it, I can't say for sure who the main characters are. They could be young heroes on a quest, or perhaps scholars researching the leviathan.
There could be a protagonist who is an outcast in society but discovers that they have a unique ability to communicate with the leviathan. Alongside them, there might be a group of friends or allies, such as a thief who has valuable skills in sneaking around and finding hidden places, a mage who can use magic to defend against the threats that come with the search for the leviathan, and a healer who ensures that the group stays alive during their adventures related to the leviathan.
I'm not sure specifically as I haven't read this particular 'leviathan full novel'. But generally, in a novel with such a title, the main characters could be those who interact with the leviathan - like concept. It might be a hero who tries to confront it, or a group of people affected by its presence.
Not having read the 'leviathan graphic novel', we can only guess at the main characters. It's possible that there's a young protagonist who stumbles upon the mystery of the leviathan. This character could be an outcast or someone with a unique perspective. There might also be an older, wiser figure like a mentor who helps the protagonist understand the nature of the leviathan. Additionally, there could be a group of characters, perhaps friends or comrades of the protagonist, who join in the adventure or the struggle related to the leviathan. Their different personalities and skills would add depth to the story and how they interact with the main threat or mystery that the leviathan represents.
There's Jim Holden. He's a key character, very much an idealist who gets caught up in a web of interplanetary intrigue. And then there's Miller, a detective with his own set of problems and a rather jaded view of the world.
One of the main characters is Jim Holden. He is a complex character who often finds himself in the middle of various dangerous situations.
The main character is Percy Jackson. He has his own set of powers and a destiny to fulfill. Alongside him, we often see characters like Nico di Angelo. Nico's dark powers and his knowledge of the underworld can be a great asset in the battle against the Leviathan. Also, there could be some sea - related deities or creatures that become important characters in the fanfiction, as the Leviathan is a sea monster. They might either help or hinder Percy's quest.
I haven't read it in detail, but generally it might involve a story set in a fictional world with its own set of rules and characters. Maybe there are elements of adventure, magic or some sort of power struggle.
The main character is likely the OC, the son of the original Leviathan. There may also be other characters from the DxD universe such as Issei, Rias, and other devils, angels, or fallen angels.
I'm not entirely sure as I haven't read it specifically. But generally, a light novel often has elements like interesting characters, a unique plot. It might be about a story where 'leviathan' is a central figure, perhaps a creature or a symbol in a fictional world filled with adventures, magic or some sort of complex relationships among the characters.
The characters included the male lead, Yang Junyu, who only ate but didn't poop. "A Kun in the Stomach" by Little Red Frog. It was a sci-fi/interstellar civilization novel with elements of evolution, future world, and opening flow. User recommendation: "A Kun in the Stomach" is a very good book. The author brought the readers into a wonderful fantasy world with his unique storyline and vivid descriptions. The characters depicted in the book were vivid and interesting, making people feel as if they could personally feel their emotions and experiences. The story was fascinating and irresistible. This book was not only a fantasy novel, but also a story about growth, courage, and faith. In the process of reading, the readers could not only enjoy the story, but they could also get some inspiration and thoughts from it. Overall, this was a good book worth reading. I hope you will like this book.
I don't know specifically which 'leviathan novel' you're referring to. There could be many novels with that name or a related title, each having different authors.