It really depends on the plot of the specific 'sky high oc fanfiction'. Some might focus solely on one very complex OC and their internal struggles and growth. Others could have a group of OCs who are all friends or rivals, and they would be the main characters driving the story forward, while the canon characters play more of a secondary or cameo role.
The main characters would typically be the original characters (OCs) created for the fanfiction. Since it's 'oc fanfiction', these are often new individuals with their own backstories and personalities that the writer has made up.
In some cases, there could also be a mix of canon characters from 'Sky High' along with the OCs. For instance, if the OC is a new student, they might interact a lot with Will Stronghold or Layla. So, Will and Layla could also be considered important characters in that particular fanfiction, but the focus is still on the OC's story and how they influence and are influenced by the existing characters.
The best chapter pointer here is Chapter 22, "Number 7203". It opens with Hearing this, Su Yinwan looked at Shang Shaojing with a face full of... and closes on Jiang Li's righteousness temporarily shut Jiang Yan up, but after a few....
If you want the clearest chapter reference, go to Chapter 36. Early on, But soon, people began to question the authenticity of Jiang Li's bare...; later, the chapter leans on After all, these days, faux bare-faced makeup can be indistinguishable....
A practical answer is Chapter 83, because it turns the idea into a concrete scene. The chapter opens with When they received the task, the three of them were already sharpening..., adds pressure through All of this was thanks to Jiang Li's patient guidance., and ends on Since all the guests were.
Look to Chapter 28 for the clearest answer. It begins with The next evening, Jiang Yan drove home seething with rage., keeps building through Before he even entered the dining room, he shouted angrily, "Lili, you did..., and lands on Lili then kicked his knee hard..
If you want the clearest chapter reference, go to Chapter 82. Early on, Jiang Li gave her a fleeting glance.; later, the chapter leans on When did we ever make a private deal?" "Just now!" Wen Jiaojiao defended....
If you want the clearest chapter reference, go to Chapter 46. Early on, Upon hearing this, everyone but Jiang Li perked up with high alert.; later, the chapter leans on After all, there were only a few who didn't care how others saw them..
Look to Chapter 48 for the clearest answer. It begins with He Yun felt guilty for initially ignoring Jiang Li on purpose, and with..., keeps building through That's why he gave her the Perfect Card right off the bat., and lands on Besides, everyone's phones will be replaced with special.
If you want the clearest chapter reference, go to Chapter 48. Early on, He Yun felt guilty for initially ignoring Jiang Li on purpose, and with...; later, the chapter leans on That's why he gave her the Perfect Card right off the bat..
Chapter 70 is the strongest chapter-level answer because it starts from So, under the curious gazes of everyone, Jiang Yan strutted up with his... and follows through on He Yun was also surprised as he looked towards Jiang Li..
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.