I don't know for sure as I haven't read it. It could be some local heroes or ordinary people with extraordinary stories.
I'm not sure specifically as I haven't read it. But generally, a ballad novel might be about some heroic or romantic tales related to the place called King's Mountain.
In the 'the king of golden mountain story', the main character is the king himself. He is likely to be a complex character, with his own desires, fears and ambitions related to the golden mountain. Additionally, there could be characters like the king's family members. For example, a prince or princess who may have a different view on the wealth of the golden mountain. There may also be characters from neighboring lands, such as emissaries or invaders, who play important roles in the story's plot as they interact with the king and his golden mountain.
In 'Bramble the Mountain King story', Bramble is the central figure. Besides him, there could be a mentor - like character, perhaps an old hermit who imparts some crucial knowledge to him. And then there are the antagonists, which might be the fierce monsters or the evil spirits that inhabit the mountain.
Since I don't know the exact 'storm king mountain story', I can't say for sure who the main characters are. They could be local people who live near the mountain, like farmers or hunters.
There could be other characters like the forest animals. They might be Bramble's friends or foes. For instance, a wise old owl that gives Bramble advice, or a sneaky fox that tries to trick him.
In this novel, the main character could be a former knight who has lost his way. He finds solace in wine while still relying on his sword skills. There might be a group of bandits as antagonists. They terrorize the villages and the main character, with his sword, has to fight them. And there could be an old hermit who knows a great deal about the history of the sword and the significance of the wine in the area. The hermit could play an important role in guiding the main character on his journey.
I'm not entirely sure as I haven't read it completely, but I assume there would be Shinigami characters as main ones. Maybe a young or inexperienced Shinigami who is learning the ropes.
Since I haven't read it, I can't say for sure. But given the title, Sophie is likely to be one of the main characters. There could be other characters like her friends, family members, or perhaps antagonists who play important roles in the story.
As the title implies, Yaya is probably a central figure. There could be a mentor figure in the graphic novel who helps Yaya on her journey. Or perhaps there's a love interest for Yaya. Another possible main character could be an antagonist who creates conflict for Yaya.
I don't know as I haven't read it, but it could be the person who aims to conquer the mountain, who would be the protagonist. There might also be some mentors or helpers along the way.