Karan Seth was paid by Ramola Sikand to prove that Shaina was Maansi, so that the will was nullified. Karan wanted Maansi's property that she had left to Baba. He kills Baba and proves Kunal guilty of it. Kunal realizes that Shaina is truthful and is not Maansi. Shaina plays Devika Maansi's role to trap Karan and Ramola and to save Kunal. She creates misunderstandings between Karan and Ramola and so Kunal is saved.
Shaina
Devika Maansi