No God In Eden vol 1 back

A spicy BL (Boys' Love) omegaverse romance about the awakening of the very first alpha and omega! Shy, introverted Takai Shikito has spent most of his life with his head in a book. He's the complete opposite of his classmate, the handsome and charismatic Nishio Ririto, whom he's always admired. The two have little reason to speak to one another-until one day, when Takai notices an alluring scent coming from Nishio. Later, during gym class, a strange feverish heat suddenly overtakes Nishio, and he begs Takai to help him. But rather than take his classmate to the nurse's office, Takai finds himself alone with Nishio in a storage room, the heat in his own body almost unbearable. Little do these two know that they are about to become the world's first alpha and omega, witnesses to the birth of the omegaverse...