A theme that's not as obvious but still common is redemption. Sometimes, the deal is made as a way for Cas or Dean to redeem themselves. Maybe Cas has made a mistake in the past and he thinks this deal will make up for it. Or Dean feels guilty about something and the deal is his way of trying to fix it. These themes all come together to create really engaging 'Cas makes a deal with Dean' fanfics.
Trust is also a big theme. When Cas makes a deal with Dean, they have to trust that the other will uphold their end of the bargain. In many fanfics, there are moments of doubt where one of them questions if the deal was a mistake. And of course, the theme of love, whether it's platonic or more, is always present. The deal often brings out deeper emotions between them, and they realize how much they mean to each other.
Chapter 12, "Drunk to the point of not being able to distinguish people after just two bottles?", is the clearest early answer because it turns Lin Manru's situation into a concrete plot event.
Chapter 331, "Zhu Shun and Huang Tianxi, the 3rd Year Cold Yuan Banquet of Great Xia, and Xia Yuzong (Part 5)", is the clearest early answer because it turns Huang Tianxi's situation into a concrete plot event. Early on, The children immediately lowered their heads in fear, Huang Tianxi.... By the end, The Seven Departments in the Outer City East, South, West, and North....
Chapter 339, "The Changes of Li Hu and Yang Zhong, the Hou Family's Opportunity, Advice (Part 3)", is the clearest early answer because it turns Li Tiancheng's situation into a concrete plot event. The setup is Speaking of this, Li Hu paused slightly, his pupils revealing a look..., but the pressure keeps building through Even if we trained to death, we might not compare." Yang Zhong's....
Chapter 98, "Jiang Li is So Daring!", is the clearest early answer because it turns Feng Shui's situation into a concrete plot event. The chapter gives readers a real answer by opening on Jiang Li listened to the end and didn't have much of a reaction, only...
Chapter 266, "Assessment Objective, Hell Level Difficulty", is the clearest early answer because Qiu Peng finally turns buildup into a real advancement. The setup is So scared before it even starts?" "Teams of a hundred, weapons, bows..., but the pressure keeps building through you can bring everything you can carry, and the Cold Beasts have....
Chapter 293, "The Lion Hunts the Rabbit – Luring the Enemy and Falling Into a Trap (Part 2)", is the clearest early answer because it turns Wushuang's situation into a concrete plot event. A useful checkpoint is the way the scene starts with What's happening at the back?" "I took Hong Guang and Hong Tian, six... and follows through with That Great Xia had left a thousand troops in Hanqiong wasn't a secret..
Chapter 290, "Rich Harvests—Should We Store Land or Men?", is the clearest early answer because it turns Song Yuan's situation into a concrete plot event. It opens with The price of the great victory at Ning Yuan Hill was clearly much... and closes on This has nothing to do with how many results were achieved, the....
Chapter 327, "Beast Tide Showdown, the Wolf King’s Gambit, and White Dew Gu’s Last Stand", is the clearest early answer because it turns Frost Wolves's situation into a concrete plot event. The chapter gives readers a real answer by opening on A sudden whirling wind abruptly interrupted Xia Hong's train of... and ending on Even if the rear managed to shoot arrows, the raging airflow caused....
Chapter 288, "On the March, Hou Hu's Wrath", is the clearest early answer because it turns Hou Hu's situation into a concrete plot event. The setup is A bit faster, it's been half an hour and we've only covered a..., but the pressure keeps building through Too slow." "The people pushing and pulling the carts, pack all the....
Chapter 298, "Hou Jing Surrenders, White Abyss Falls, Zhaoyang Changes Its Flag", is the clearest early answer because it turns Hou Jing's situation into a concrete plot event. It opens with Hou Kong is twenty-six this year, has a Superior Battle Body, and his... and closes on If I win, I will release Hou Bing as agreed, how about it?" If I....