Another theme could be a sort of opposites - attract relationship. If the OC is very energetic and positive, compared to Murasakibara's more laid - back and sometimes grumpy nature, it can create an interesting dynamic. They might start off not getting along but then gradually fall in love. And this kind of relationship development is quite common in such fanfictions.
One common theme is the OC helping Murasakibara grow as a person. Since he has his own quirks and insecurities in the original story, the OC can be written as a positive influence on him.
A third common theme is the exploration of Murasakibara's love for food in relation to the OC. Maybe the OC is a great cook and uses food to bond with him. Or perhaps they meet in a food - related setting like a bakery or a restaurant. This theme ties in well with Murasakibara's character trait of loving snacks and food in general in the Kuroko's Basketball series.
Chapter 845, "Turns Out He is the Body Double!", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event. Early on, During these two hours of waiting for the results, the restaurant was....
Chapter 899, "It's actually a seal script?!", is the clearest early answer because it turns Rong Kexi's situation into a concrete plot event. Early on, Jiang Cheng, with his head dizzy, was pulled into the courtyard by....
Chapter 854, "These Brothers Are Quite Lacking in Love", is the clearest early answer because it turns Ji Yanbai's situation into a concrete plot event. Early on, If this bracelet gets bumped anywhere, she'll be heartbroken, right?.
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 906, "Big Brother, are you jealous?", is the clearest early answer because it turns Jiang Buchen's situation into a concrete plot event. The chapter turns that into something concrete by moving from A few people were somewhat surprised.
Chapter 801, "This Elder Sister Is So Smart", is the clearest early answer because it turns Jiang Buchen's situation into a concrete plot event.
Chapter 740, "Someone Who Can Live Through the Days", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event. The chapter turns that into something concrete by moving from Fang Kai sprang to life when he heard this, immediately setting his...
If you want the clearest chapter reference, go to Chapter 8. Early on, The resentment that had barely calmed among the crowd surged back two...; later, the chapter leans on Some of them were relatives of the Jiang Family, who felt it improper to....
Chapter 708, "Stinky Beggar", is the clearest early answer because it turns Star Media's situation into a concrete plot event. The chapter turns that into something concrete by moving from Chen'an's executives feared that the situation would escalate and...
Chapter 693, "Is a Man's Prime That Short?", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event. It opens with Zhao Lang had never anticipated that the bravado he had shown earlier... and closes on Didn't you have dinner?" "No," Jiang Cheng pouted..