I don't know for sure as I haven't read it. But it could have a brave protagonist, perhaps a young adventurer who is drawn to the mystery of fire and stone.
There could be a character who is an outcast in society but discovers a special connection to fire and stone. This character could be the main focus, and along the way, they meet others. Maybe there's a female warrior who is also interested in the power of fire and stone for different reasons, like protecting her tribe. And there could be a mysterious figure who appears only in times of great need, related to the ancient lore of fire and stone, guiding the main characters on their journey.
It's possible that there is a group of diverse characters including both humans and aliens. The humans could be a team of astronauts or researchers. Among the aliens, there could be a leader figure. These characters' interactions, their hopes, fears, and their quests within the context of the alien world with fire and stone elements would drive the story forward in the graphic novel.
Since it's a graphic novel, there might be a group of adventurers as the main characters. One could be a strong and silent warrior type, who is physically capable of protecting the stone heart. Another could be a clever thief who has the skills to steal or retrieve the stone heart from dangerous places. And there could be a wise scholar among them, who can decipher the ancient texts and clues related to the stone heart's origin and power.
I'm not familiar with the 'stick and stone graphic novel' in detail, but if it follows the obvious, then Stick and Stone would be the main characters. There might also be other supporting characters like animals or other elements of nature that interact with them in the story.
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.
In 'the wings of fire graphic novel', the main characters include Tsunami, a SeaWing dragon. She is brave and very good at swimming. Another important character is Glory, a RainWing dragon. She has the ability to change her color for camouflage. These characters, among others, play crucial roles in the various adventures and conflicts in the story.
Clay is one of the main characters. He's a MudWing dragonet.
It could be that the main characters are the arsonist, if it's a story about an intentionally - set fire, and the detective or investigator trying to catch them. Or it could be a group of neighbors who come together during the fire to support one another. Each character would bring their own perspective to the story. The illustrator would likely use different styles and details to show their personalities, like a shy neighbor might be drawn with hunched shoulders and a worried expression, while a confident firefighter would stand tall and have a determined look on their face.
The main characters are a group of dragonets. Clay is a MudWing, strong and kind - hearted. Tsunami is a SeaWing, brave and sometimes a bit impulsive. Glory is a RainWing, with her unique abilities and a sassy personality. Starflight is a NightWing, intelligent but often over - thinks things. And Sunny, a SandWing, who is small but full of determination. All of them play important roles in the story of 'Wings of Fire 1 Graphic Novel'.
I don't know as I haven't read it. But it could be a group of sailors, pirates, or people living near the water. Maybe there's a brave hero who has to deal with the 'fire on the water' situation.
I'm not sure as I haven't read it. But based on the general 'Wings of Fire' series, it could be dragons like Clay, Tsunami, Glory, etc. who might continue to be main characters in this graphic novel too.