Hwanhyeol

The Ryu brothers, Ryu Hyeon and Ryu On, raised in the same room, the same house, the same time. Ryu Hyeon, praised by the world as the noble and perfect eldest son, is in fact neither man nor woman, bearing a ‘defect’ in his body. To carry on the line, he receives seed from unknown men. One day, Lord Yun, their father, reveals his secret plan to Hyeon: to conceive a child with his own brother, Ryu On.

"How could you bear the seed of a mongrel? Receive superior seed to produce something superior."

(Source: MrBlue, translated)

Note: Includes two extra chapters.