00ac's manga / #Betaxomega(1)

Set in the omegaverse where there are three SECONDARY genders: alpha, beta, omega. While alphas and omegas have pheromones and cycles (heat/estrus, rut) that are all around sex with the intentions to either mate/find a partner or reproduce. Betas don't have the ability to sense other's pheromones, and also aren't privy to ruts/heats/estrus. Our MC (who tops by the way) is the oblivious Mr.B, a beta, who lives his life trying to be a decent️ human being. If he sees an omega going into heat, he will help them, not take advantage of them. One day, however, he meets our ML, who seems to capture even him with his addictive pheromones and the immovable Mr. B, crumbles in response. However, he doesn't know everything Moon, our ML... I personally enjoyed the plot twist very much.