According to a Korean commenter [spoilers below!!]
The stepmother had been secretly and consistently giving Jaeha drugs to turn him into an Omega in order to make her son the heir. Taegeon found out about this through his investigation, and since the way to prevent him from becoming an Omega was to have sex and release pheromones during every rut—or something like that—he kept helping him. Later, after Jaeha found out, he had the choice of becoming an Omega or remaining an Alpha, and since he chose to be an Omega, he even has a child in the side story
Boo
Holy fudge- (⊙…⊙ )
It was very evident when a supposed 'dominant' alpha doesn't recoil to another's scent, another point is how the recessive alpha brother is able to pick up sweet scent from his brother when he got exited, albeit briefly.
Is it true the bottom turns into an omega? I wanna know before I start this because i don’t wanna waste my time