One common theme is the contrast between their personalities. Marshall Lee is a vampire and has a bit of a dark, cool side, while Gumball is more upbeat and innocent. Fanfics often play with this contrast. Also, discovery is a theme. They might discover new places or powers in the fanfics. For instance, they could find a hidden realm in the Adventure Time world that only they can access because of their unique bond.
Friendship is a common theme. Since they are from different worlds (Marshall Lee from Adventure Time and Gumball from his own show), exploring how they become friends is often in the fanfics. Another theme is adventure. They usually go on some sort of journey together.
The themes of acceptance and mutual understanding are quite prevalent. Given their differences, fanfics show how they come to accept each other's quirks. There's also the theme of facing challenges together. Whether it's a magical curse or a powerful enemy, they work as a team. In some fanfics, there's also the theme of cultural exchange, as Gumball brings his own set of values and behaviors from his world, and Marshall Lee does the same from Adventure Time.
Chapter 627, "Definitely Not an Accident", is the clearest early answer because it turns Don's situation into a concrete plot event. The chapter gives readers a real answer by opening on He looked at the sinister smile lingering in Jiang Li's eyes, then at...
Chapter 228, "Younger Brother is the Number One Hater?!", is the clearest early answer because it turns Mr's situation into a concrete plot event. Early on, Huo Ziyang had not stepped out of the house for a whole week..
Chapter 456, "It's Not Too Much to Ask for a Game Console, Right?", is the clearest early answer because it turns Yu Li's situation into a concrete plot event.
Chapter 238, "The Guests Were Dumbfounded, The Audience Was Excited", is the clearest early answer because it turns Zhao Lang's situation into a concrete plot event. The chapter gives readers a real answer by opening on Jiang Li was actually first on all three leaderboards?!
Chapter 188, "First in Grade, It Can Only Be Me, Jiang Cheng", is the clearest early answer because it turns Shang Shaojing's situation into a concrete plot event. A useful checkpoint is the way the scene starts with With a "snap," the pencil Jiang Cheng was using to draw broke on the...
Chapter 417, "The Real Struggle for Survival has Just Begun", is the clearest early answer because it turns Nina's situation into a concrete plot event.
Chapter 333, "The Clothing Design Room", is the clearest early answer because it turns Lin Manru's situation into a concrete plot event. Early on, [LOL, the little brother turns out to be socially anxious too, he.... By the end, You've been cooped up in your room all week staring at this book;
Chapter 582, "Fleeing Hastily", is the clearest early answer because it turns Guo Xing's situation into a concrete plot event. Early on, Luo Xuan pushed her away, disappointment filling his eyes.. By the end, Only Ai Xiaochun, lacking the strength to go on, was left behind and....
Chapter 573, "You Are Already Ugly Enough", is the clearest early answer because it turns Chen Manman's situation into a concrete plot event. It opens with Social work was the major I switched to for balance, my minor is in...
Chapter 367, "Help Me Call the Police", is the clearest early answer because it turns Chixia Village's situation into a concrete plot event. Early on, However, before they could approach, another loud "bang" sounded as....