Harry Potter (character)
In the books, Harry's scar serves as an indicator of Voldemort's presence: it burns when the Dark Lord is near or feeling particularly murderous or exultant. According to Rowling, by attacking Harry when he was a baby, Voldemort gave him "tools (that) no other wizard possessed – the scar, and the ability it conferred, provided a magical window into Voldemort's mind." Asked why Harry's forehead scar is lightning bolt-shaped, Rowling said, "to be honest, because it’s a cool shape," and joked, "I couldn’t have my hero sport a doughnut-shaped scar."