An Inconspicuous Passerby Becomes the Protagonist of a Romantic Comedy

Japanese light novel + multiple heroines + daily campus love + multiple perspectives + party struggle He is sunny and handsome, versatile in literature and sports, has a prominent family, and is supported by many stars; he is assigned to the same class as a mysterious girl who he has had a crush on for a long time and a blond childhood sweetheart who suddenly transferred to another school. The cutest black long straight girl in the next class is talked about by everyone and also likes him; in addition, he also has a sister who is as beautiful as a fairy. He looks like a hero who is about to embark on a dazzling and eye-opening romantic comedy life. Unfortunately, this is not me. I am just a "shady" marginalized friend of the protagonist. I am just a passerby in the story. Other than that, there is no need to mention anything. What will happen if a passerby character who has never been favored by the goddess of luck, never won the heart of the object of his admiration, and has never had a happy ending is drawn into the love whirlpool of the protagonists?