Responses
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He tricked yiyun into caring for rourou as he was unable to claim rourou as his own son. He needed rourou to be born, but wanted someone else to take care of him. If his family got to know that he has a son, then they could harm him.. so he made yiyun believe rourou is his son so that yiyun could raise him.
It seems as though many ppl are confused about the story so ill try to clear somethings up.
•Yiyun went abroad to have a child and had Rourou.
•however, it was revealed that Rourou isnt biologically yiyun's instead he is biologically Jinyao's
• when Rourou was born, jinyao was unable to care for him atm so he gave him to yiyun to take care.
•Yiyun's embryo was preserved by Jinyao BUT jinyao's aunt (the nice one) stole it as she was unable to have kids
•I think she thought the embryo was Jinyao's (therefore, bloodline is not ruined?) (Im not sure)
•Jinyao knows the embryo was stolen but is still unaware that it was his aunt that stole it.
•meanwhile, on the other hand, yiyun's embryo (now auntie's child) is born.
•yiyun just found out the existence of his embryo.