Well, an OC could be a new teacher's assistant at Hogwarts. In this role, they would interact with the main characters in a more mentoring - like way. They could offer advice on difficult spells or help them with their homework. Another way is if the OC is a healer in training at St. Mungo's and the main characters end up there due to some magical mishap. The OC would then take care of them and get to know them during their stay. Also, the OC could be a journalist for the Daily Prophet, interviewing the main characters about their latest heroic deeds or controversial actions.
They could be classmates. For example, if the OC is in Gryffindor, they can study with Harry, Ron, and Hermione, participate in Quidditch practice together, and get into adventures in the Forbidden Forest. Or they could be rivals, like an OC from Slytherin who always tries to outdo Harry in every magical test or duel.
Chapter 388, "All the Rich People in Jing City Are in Jiang Li's Live Room", is the clearest early answer because it pushes Rich People into a new phase or setting. Early on, what, what do you plan to do?" Gu Yu's false identity was never meant....
Chapter 411, "You Really Hold a Strong Grudge", is the clearest early answer because it turns Hua Country's situation into a concrete plot event. It opens with The lead director, who understood the entire process, had an...
Chapter 233, "Individual, Ten, Hundred, Thousand... Million, Ten Million, Damn!!!", is the clearest early answer because it turns Tianyi's situation into a concrete plot event. The chapter turns that into something concrete by moving from [What the hell, what's this about life span ending??
Chapter 338, "The Adulterer is Far on the Horizon, Yet Close Before the Eyes", is the clearest early answer because it turns Li's situation into a concrete plot event. Early on, Tang Jinyu, dressed in a light apricot Cheongsam, sat indifferently....
Chapter 210, "Are All of Jiang Li's Fans Hidden Big Shots?", is the clearest early answer because it turns Miss Jiang's situation into a concrete plot event.
Chapter 463, "Even if it's a Wild Boar, I'm Willing!", 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 The evening glow gradually bathed Dragon Ridge Island in a dazzling...
Chapter 587, "Has He Also Become a Part of the Play?", is the clearest early answer because it turns Isn's situation into a concrete plot event.
Chapter 137, "Lai Fu's Death Has Another Cause", is the clearest early answer because the violence around Aunt Ying becomes final instead of hypothetical. Early on, Jiang Li personally went to Lai Fu's tomb and performed a small....
Chapter 306, "I Believe Whatever Miss Jiang Says!", is the clearest early answer because it turns Jiang Says's situation into a concrete plot event.
Chapter 669, "My First Love Sister Who Died Young", is the clearest early answer because it turns Xi Yang's situation into a concrete plot event. The chapter turns that into something concrete by moving from Bang," the door closed, but Chen Qijun's words lingered in Tai Fan's...