Since I haven't read the novel, I can't say for sure. But likely there is the character who has to make the choice between hero and demon lord. There might also be some sort of mentor figure for each path, like an old wizard for the hero side and a powerful dark entity for the demon lord side.
I'm not sure about the exact plot of this novel. It might be about a character who is given the choice between becoming a hero or a demon lord, and then the story unfolds based on that choice, with different adventures, challenges, and moral dilemmas that come with each option.
Another important character could be an oracle or a seer. This character might have foreseen the hero's transformation but was not believed. Their presence can add an element of fate and inevitability to the story. Also, there may be a group of followers who were loyal to the hero but then have to decide whether to follow the new demon king or oppose him, which can create interesting internal conflicts within the group.
Another theme might be friendship or the potential for it. Despite their opposing roles, there could be moments where the demon lord and the hero understand each other on a deeper level, blurring the lines between their two worlds.
Well, the demon lord himself is likely to be very interesting. He probably has a complex backstory that led him to become the demon lord. His motives might not be as straightforward as just being 'evil'.
Well, usually it might involve intense battles between the hero and the demon lord, along with character development and a complex plot.
As I'm not familiar with this specific light novel, it's hard to say who the main characters are. But it's likely that there is a demon lord character at the center of the story. There may also be characters who oppose the demon lord, like a group of brave warriors or mages. Maybe there's a special character who has a connection to the demon lord from the past or something like that.
The demon king is surely one of the main characters. He must have some unique characteristics, like great power and a complex personality. The hero is another main character. He could be a young and brave individual with some special abilities. And there may be other important characters, for example, a wizard who has some connection to the summoning spell or a princess who the hero is trying to protect in his own world and that affects his actions in the demon king's realm.
Another theme could be redemption. Maybe the negative hero is trying to find a way to redeem himself through his interactions with the demon lord army leader and the situations they face together. It could also involve themes of power and its corrupting influence. The demon lord army leader represents power, and the negative hero has to navigate how this power affects him and the world around them.
It shows a complex and evolving relationship. At first, they are enemies, but as the story progresses, there's a hint of mutual understanding.
The manga 'Demon Lord Saves Hero' crafts their relationship by throwing them into challenging situations together. This forces them to work together, revealing hidden sides of their personalities and leading to a deep, unconventional connection.