In the gripping web novel 'I Should Have K*lled My Sister,' the story unfolds around twin sisters who were once childhood friends of the protagonist. The elder sister's torment and bullying drive the protagonist to a tragic end, leading to haunting regrets. Written originally in Japanese, this emotionally charged narrative delves into themes of drama, psychology, romance, and tragedy, offering a poignant exploration of the consequences of bullying and its lasting impact on relationships.