Well, dealing with Manhwa 40 could depend on various factors. You might need to consider the genre, the plot, and your personal preferences. Maybe start by understanding the main themes and characters to better approach it.
Add a lot of mystery. Don't reveal all the details of the deal right away. Let the readers wonder what exactly the devil is getting out of it and what the full implications of the deal are for the character. For example, if the deal is about getting revenge on someone, make the revenge seem simple at first but then show how it spirals out of control.
Gon could be a likely character. He is extremely determined and has a strong sense of justice. In a situation where he is faced with an impossible task, like saving a dear friend who is on the verge of death, he might be tempted to make a deal with a devil. Another one could be Hisoka. He is always seeking power and new thrills. A deal with a devil to gain some unique and powerful Nen ability would be something that might appeal to him. Killua is also a possibility. He has a dark past and has always been in a struggle between his good side and the assassin training he received. If he thought a deal with a devil could protect his friends or atone for his past sins, he might consider it.
To handle Chapter 59 of the manhwa, first, make sure you're familiar with the main characters' motivations. Then, notice the details in the art and how it contributes to the story. Sometimes, discussing it with other fans can give you new perspectives.
You need to carefully analyze the plot and character developments in Chapter 12. Understand the conflicts and look for possible solutions or resolutions.
For Chapter 26 of the manhwa, first, pay attention to the dialogue. It often contains important cues. Also, notice the art style and how it conveys emotions and actions. Sometimes re-reading can offer new insights.
The devil in manhwa can take many forms. It could be a traditional evil character with horns and a pitchfork, or it could be a more symbolic representation of evil or temptation. It all comes down to the imagination of the author and the message they want to convey through the story.