Since the title is 'the devil and his sacrifice novel', it may follow a plot where the devil has some sort of need for a sacrifice. Maybe it's part of a dark ritual to gain more power, or it could be a sacrifice demanded as part of a deal. The story might also show how the characters react to this concept of sacrifice to the devil, whether they resist or are forced into it. There could be elements of horror, mystery and the exploration of good and evil in this novel.
I don't know as I haven't read it. But it's likely that the devil is one of the main characters. And perhaps there's someone who is the sacrifice or a character who tries to prevent the sacrifice.
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.
To survive, you should build alliances with the right characters. Also, stay away from obvious traps and don't trust everyone easily. Keep a low profile when necessary.