Pagal Nilavu written update, May 21, 2018: Truth about Karthik’s birth revealed

In the latest episode, while Karthik is driving, Azhagar calls Karthik and asks him to come to the park nearby. Azhagar introduces Doctor Devi who took care of Karthik's birth in the hospital, 25 years ago in Delhi.
As per Andal and Azhagar’s wish, Doctor Devi comes forward to speak the truth to Karthik. Doctor Devi says, she was not sure as to how Revathy and Sakthivel would react to the truth about Karthik’s birth and conveyed all the truth to Mr and Mrs Azhagar 6 months ago instead.
Doctor Devi also says that, she was the one who took care of the delivery of Revathy in Delhi and she has all the relevant documents with her. She adds that another lady named Shantha was admitted in the same ward, where Revathy was admitted for the treatment. During the delivery, Shantha was unconscious and was in a mentally affected state at that time. That is when she delivered Karthik and died and hence could track any further details about her or her family.
Devi also added it was during that time, Revathy also gave birth to her child, but that child was born dead. During her child delivery, Revathy was all alone. In order to find a family for the orphaned child (Karthik) and to save Revathy from sadness, Karthik was presented as Revathy’s child. Whenever the Doctor wanted to convey the truth to Revathy and her family, she was fearing not to disturb the happiness in their family.
Finally, Devi hands over all the medical reports about him and his real mother Shantha to Karthik. The doctor advises Karthik to hide the truth.
As requested by Devi, Azhagar too puts forth the same request to Karthik to conceal the truth.
Azhagar advises that, if Malar comes to know about these facts, Malar might ask him to leave.
Finally, Azhagar requests Karthik not to take any extra rights over Revathy and tells him to stay away from her. Karthik is shell-shocked after knowing all the facts about his birth.
Meanwhile, Sneha is tensed about being locked in the room alone. Suddenly, Sneha remembers about an old mobile in the room and tries to call Arjun from that mobile.
Sneha conveys the present situation of her to Arjun. Fearing about some disturbances from Dileep / Ramya, Sneha cuts the call.
On the other hand, Arjun is called to have dinner along with Malar, her brother, and Tamizh. During which, instead of uttering the name Tamizh, he says the name Sneha, which shocks everyone around.