I remember Jaya mentioning her sister's birth star as Kettai in the temple. To my knowledge , there is this stupid belief that a girl with this birth star should marry only the eldest son. If married otherwise it will adversly affect the elder son. [why & how....who knows ? ]Writing this from personal experience as my parents went thru this ordeal during my mapiLLai Thedal days way back in early seventies.Sad to say this archaic practice is still in existence. My guess is Nalini might use this trump card to paduthufy everyone in kalyani household.
All these serials follow the same formula.....too good people , villains , villies , cry babies. This serial also no different from others.I know its too early to comment. Let us wait & watch.