I'm not entirely sure without reading the specific novel in detail, but typically there would be a protagonist who is at the center of the story. There might also be an antagonist who opposes the protagonist's goals or values.
In many novels with such a title, there is often a complex hero. This hero may have a past that is intertwined with the scarlet and the black elements. There could be a mentor - like figure who guides the hero at times. Additionally, there may be villains who are directly or indirectly related to the opposing forces of the scarlet and the black, and their actions drive the plot forward by creating obstacles for the main characters.
The female lead is one of the main characters. She is usually the one who travels through time and gets involved in the court affairs.
The main characters are Hester Prynne, a woman who is forced to wear the scarlet letter 'A' for adultery. Then there is Arthur Dimmesdale, a minister who has a secret relationship with Hester. Roger Chillingworth, Hester's husband, is also a main character. He is consumed by revenge after finding out about Hester's affair.
The two main characters are Sherlock Holmes and Dr. Watson. Holmes is the brilliant detective with extraordinary deductive powers, and Watson is his loyal friend and assistant who often documents their adventures.
Well, of course, Hester Prynne stands out as a main character. She is strong - having to face the whole town's judgment while raising her daughter. Arthur Dimmesdale, the conflicted minister, is also a main character. His relationship with Hester and his own internal turmoil is a major plot point. And Roger Chillingworth, whose actions are driven by his jealousy and need for revenge against the man who had an affair with his wife.
The main character is Scarlet Evergarden, of course. She is the central figure whose journey we follow. Another important character is Gilbert Bougainvillea, who has a significant connection to Scarlet's past. There are also various clients that Scarlet writes letters for, like the young girl who wants to write to her mother, and they play important roles in Scarlet's growth and understanding of emotions.
Well, aside from Scarlet, there might be other characters who are affected by the contents of the letter. There could be a villain or an antagonist who tries to prevent Scarlet from getting or understanding the letter. There might also be friends or allies of Scarlet who help her decipher the letter or deal with the consequences of what's in it.
There could also be antagonists in the story. These characters would oppose the protagonist and create conflict. They might represent the forces of oppression or the chaos that the protagonist is trying to overcome, whether it's an individual or a group within the setting of the novel.
The protagonist is Pino Lella. He is a young Italian boy who experiences a great deal during the war and has to grow up quickly.
I'm not sure exactly without more specific information about this particular 'scarlet heart chinese novel', but often there could be a female lead who is caught in the web of court life.
The main characters are Hester Prynne, a woman who is publicly shamed for committing adultery and is made to wear the scarlet letter 'A'. Arthur Dimmesdale, a respected minister who is secretly Hester's lover and the father of her child. And Pearl, Hester's daughter, who is a complex and somewhat wild child. Roger Chillingworth, Hester's estranged husband who arrives in town and seeks revenge on the man who had an affair with his wife.