In Gru x OC fanfiction, a common trope is the 'secret identity' trope. The OC could have a secret that Gru discovers over time. There's also the 'mentor - mentee' trope where Gru teaches the OC something valuable. For example, how to be a better villain or just how to take care of the minions. The 'found family' trope is also seen, where the OC becomes part of Gru's odd family unit with the minions and the girls.
One popular trope is the 'fish out of water' situation. The OC, being new to Gru's world, has to adapt to all the craziness. Another is the 'enemies to lovers' trope. Maybe at first, Gru sees the OC as a nuisance but then falls for them. And the 'rescue' trope is also common. The OC gets into trouble, and Gru has to save them, which deepens their connection.
Some popular tropes include the 'accidental meeting' trope. The OC and Gru meet in a completely unexpected way, like at a fair or during a heist gone wrong. Then there's the 'power imbalance' trope. Since Gru is a powerful villain, there could be a power imbalance between him and the OC at first, which they have to work through. Also, the 'redemption' trope can be used, where Gru's actions towards the OC lead to his own self - redemption.
A practical answer is Chapter 12, because it turns the idea into a concrete scene. The chapter opens with Qin?" Jiang Li called out twice, and only then did Mrs., adds pressure through How could he have been so drunk today that he mistook someone's identity?, and ends on The glass shattered on the.
Chapter 37 is the strongest chapter-level answer because it starts from The barrage was suddenly filled with hahas, but the two guests present... and follows through on I look forward to your guidance." He Yun nodded slightly, then continued....
Chapter 18 is the strongest chapter-level answer because it starts from In the corner, a girl in a black dress sat quietly, holding a glass of... and follows through on Hurry home, what is a young lady like you doing running to a place like....
A practical answer is Chapter 25, because it turns the idea into a concrete scene. The chapter opens with Therefore, from his childhood, Jiang Shixu had felt an extreme aversion to..., adds pressure through When she saw the woman behind the desk, she smiled and said, "Look who..., and ends on.
A practical answer is Chapter 17, because it turns the idea into a concrete scene. The chapter opens with Jiang Li glanced at Jiang Shixu, who was tense and anxious behind her, and..., adds pressure through That girl who puts on makeup like a ghost deserves to be called naturally..., and ends on.
If you want the clearest chapter reference, go to Chapter 51. Early on, Oh, okay." After uttering two syllables indifferently, Jiang Li bent down...; later, the chapter leans on By the time she reacted, Jiang Li had already disappeared at the end of....
Chapter 20 is the strongest chapter-level answer because it starts from Several people turned their heads upon hearing the sound and saw three... and follows through on So, he turned and questioned Jiang Li..
Chapter 9 is the strongest chapter-level answer because it starts from Exactly, the Qiao Family isn't that great either. and follows through on Qiao, unable to save face, slapped her daughter across the face, "Didn't I....
A practical answer is Chapter 73, because it turns the idea into a concrete scene. The chapter opens with Director Sun, tongue-tied, finally managed to squeeze out a sentence,..., adds pressure through Her favorite food is rouge goose, her favorite amusement is Dancing Gun,..., and ends on Despite.