The older sister is surely a central figure. She is likely to be a complex character, having to deal with her role as the tyrant's sister. The tyrant himself would be a key character as well. There could be other characters such as nobles or commoners who interact with them. Maybe there's a love interest for the sister too, which would add another layer to the character relationships.
Obviously, the main character is the older sister. But we can also assume that the tyrant brother is another important character. There might also be characters like advisers to the tyrant, or friends or foes of the sister in the story.
One interesting aspect could be the character dynamics. The relationship between the main character and the tyrant as siblings might bring about complex emotions and power struggles. It could also be interesting to see how the world in the novel is built around the tyrant's rule and how the older sister navigates this world.
Since I haven't read it, I can't say for sure. But I would assume the villainess and the tyrant are the main characters. There might also be other important characters like the villainess's family members or friends, or some of the tyrant's advisers or enemies.
In most Naruto older sister fanfics, Naruto is a central figure. His sister, who often has unique traits and abilities, is another main character. Sometimes, villains from the original Naruto series, like Orochimaru, might also play significant roles as they pose threats to Naruto and his sister. Also, Naruto's friends such as Sakura and Shikamaru can be involved, adding more complexity to the relationships in the fanfic.
Obviously, the woman who gives birth to the child is one of the main characters. She is likely to be the protagonist, going through a series of emotional and physical challenges. The tyrant himself is another main character. His actions and decisions would drive much of the plot, especially regarding the child and the mother.
I'm not sure who the main characters are exactly as I haven't read the novel. But I assume there would be the tyrant and the character who tames the tyrant.
There might also be a wise advisor. This character would be crucial in providing guidance to the tyrant, whether he takes the advice or not. The advisor could have his own motives and secrets, which add more depth to the story and the relationships between the characters.
I'm not entirely sure without reading it in detail, but likely the sister is one of the main characters. And there's probably a male protagonist who has a special relationship with the sister.
We can only guess based on the title. The protagonist, who holds the tyrant's heart, is surely one of the main characters. This character might be a strong - willed individual with a complex personality. The tyrant, on the other hand, is likely to be a complex figure as well, perhaps with a troubled past that led to their tyrannical behavior. There could also be a love interest or a rival for the protagonist's attention, which would also be important characters in the story.
There's no way to know precisely without reading it, but it might have a main character who is on a journey to discover the truth about the dead. Maybe there's a group of people who live near a place that is said to be haunted, and they are the main characters. They could be trying to figure out if there's a real connection between the living and the dead in that area.
Since we have no details about this novel, it's impossible to say for sure who the main characters are. However, they might include a hero or heroine who discovers the living force and has to deal with its consequences. There could also be villains who want to misuse the living force for their own evil purposes. And perhaps there are side characters who help or hinder the main character's journey regarding the living force.