Tsuyoki na Oni-sama wa Ore Dake no Ω

"If it's you, I don't mind doing it with a man." In a world filled with Alphas who have special demon powers, Hibiki is an omega who has the power to turn into a demon. He hides his identity and is on a mission to defeat monsters. Masato, his junior who can also turn into a demon, is a playboy and they don't get along well. One day, during a mission, Hibiki suddenly gets into heat and Masato finds out that he's an omega...!! "Ah, sorry, I can't hold back any longer." Masato shoves his hot dick into Hibiki's wet butt by force. A BL story between a younger alpha and confident tsundere omega who are on very bad terms!

(Source: MangaPlaza)