Kizumonogatari I: Tekketsu-hen

A second-year high school student named Koyomi Araragi becomes friends with Tsubasa Hanekawa, an academic top performer at their school. Hanekawa shares a local rumor about a "blonde vampire." Araragi, typically reserved, appreciates her approachable nature. Later that night, he meets the vampire in question—Kiss-Shot Acerola-Orion Heart-Under-Blade, known as the "iron-blooded, hot-blooded, cold-blooded King of Apparitions." She appears injured, with all four limbs severed, and begs Araragi for his blood. After complying, he wakes up transformed into a vampire. As he grapples with his new identity, Kiss-Shot tells him, "Welcome to the world of darkness."