There's no way to know precisely without reading the graphic novel. But it's possible that there's a hero - type character who is trying to save others from the lake of fire. Maybe there's also an antagonist, someone or something that is causing the chaos or danger associated with the lake of fire. The characters could be complex, with their own backstories and motives that are slowly revealed as the story in the graphic novel unfolds.
The main characters are Odette, the princess turned swan, and Prince Siegfried. Also, the evil sorcerer Rothbart is an important character.
Since it's a story about treasure in a lake, there might be a young and curious character, like a teenager. They could be the one to initiate the search. And there may be an old hermit who has some knowledge about the treasure's origin but is reluctant to share it at first. There could also be some villains who want to steal the treasure from the protagonists.
Obviously, the Lady of the Lake is one of the main characters. King Arthur might also be a major character as his relationship with the Lady of the Lake, especially regarding Excalibur, is a significant part of the Arthurian legend. Merlin could be in it too as he is often intertwined with the events and characters in this mythology.
Some of the main characters include Mr. Immortal. He has the power of immortality, which leads to some really interesting and often comical situations. Another is Big Bertha, who has the ability to transform between her normal self and a much larger, more powerful form.
I don't know for sure, but there could be a brave hero who is trying to uncover the secrets of the throne of fire.
I don't know for sure as I haven't read it. But it could have a hero who has the power to control fire and is on a quest to save the world from an ice - based villain. Or maybe there are twin protagonists, one with an affinity for fire and the other for ice, and they have to learn to work together.
There are several important characters. Clay, the MudWing, is known for his loyalty to his friends. Tsunami, a SeaWing, is brave and often takes charge. Glory, a RainWing, is also a main character. She has unique abilities and a sassy personality. These characters play key roles in the various adventures and challenges in the story.
Since I haven't read it, I can't say for sure. But it could have characters like the homeowners, the firefighters, and maybe some neighbors.
In the 'Goblet of Fire Graphic Novel', of course, Harry Potter is a central figure. He has to face the dangerous Triwizard Tournament. His friends Ron Weasley and Hermione Granger play important roles. Ron has his moments of jealousy and then support for Harry. And Hermione uses her intelligence to help Harry figure out the mysteries around the tournament. Also, there are characters like Cedric Diggory, another Hogwarts champion, and the other school champions like Viktor Krum and Fleur Delacour.
I'm not entirely sure without reading it, but it might be the dragon characters that are central to the 'Wings of Fire' series in general.