Mala created Parvati.
We the audience can run from this fact all we like, but the show would like us to know this. Rudra has known this since the day he saw the mother/daughter style picture of them in Thakur's Haveli. And symbolically, it is Mala who tells Parvati about the man who will come, one day, to take her away, to give her a life and a love which she is completely unaware of---her own son, Rudra. And leaving her son orphaned without having lost a single parent, Mala as the Thakurain chose this orphaned village girl to lavish her love on. She gives Rudra's share of her upbringing, to a lost Birpuri child she has identified as her own. Parvati is the one Birpuri bride she symbolically gifts her wedding jewellry and kangans to at the start of the show--- a gift to a daughter(wedding set) and a daughter-in-law (kangans) both.
And aside from giving Parvati away in marriage like a mother, with the belief her husband has found her a perfect match, not a horror-show of a future, Mala also teaches this girl everything she knows about goodness and female virtues. Her Mami-sa is not the one Parvati thanks for her expertise with her kalakari. She says Mala has taught her music, Mala instilled her bhakti to the god Bholenath who she herself worships. Mala has shaped Parvati's nature, her innocence, even her future. Mala needs to be a true believer if she has named her son after Shiv-ji---as she has. Thus again, Mala gives Parvati, indirectly, what she wants---a husband who is "Bholenath ki naam ka." Mala brought Parvati up in the very real sense of the word, teaching her exactly those elements of herself that Rudra is completely bestotted by today.
Mala created Parvati, and Parvati is now re-creating Mala's son. The wounds that Mala left, when she left her son home and husband for the Thakur are wounds Paro is slowly filling in---using what MALA has taught her--- the music, the kindness, the love, the devotion to her god/man. She is Mala's daughter. Adopted in all but name. She wanted to have Parvati as a daughter-in-law, for her son, someday. Her god, Bholenath, took care of that wish for her. She is why Rudra has this Parvati. We cannot hate Mala, Rudra cannot hate her, for no reason other than just this. Parvati as she is today is because Mala left Rudra, came to Birpur and became Parvati's mother. She created her son's salvation after she became the reason for his devastation.
I wold go so far as to say---Mala needed to abandon Rudra to create who he has become now as well. Rudra would not be the emotionally strong, intelligent, honorable and still devious and intimidating man he is today without that childhood abandonment, without those 15 years of hurt. If you want to see who he could have turned to, had he lived in the Haveli with an unhappy mother who stayed behind even though she clearly loved someone else, and with Kakisa having access to him for 15 years---look at Samrat or Sumer. That's who Rudra would have been like.
Mala created Parvati. Mala created Rudra. How she did it, why she did it will pale before the fact--- she did it. Nothing that happens now, no revelation in the future will change this. Rudra is a protector of good and a destroyer of evil. The Thakur, the "Evil" should be a smarter man than this. Giving back to Rudra and to Parvati the person who is their creative-force, who is BOTH their sources of maternal love is a stupid, stupid idea. It will undo the one weakness, it will repair the one broken foundation Rudra has in him, and it will give back to Parvati a mother she longs for. A mother who will give her strength to protect and support Rudra just by existing in the same house as her children. Returning Mala, in an exchange?
If I was the Thakur, I would recognize something about Mala that is really quite terrifying--when she loves you, you prosper. When she leaves you, you decay. And she does not do second chances --she loves passionately, to the extent of forgetting everyone else for that love. And when she leaves, she never turns back, never even thinks of the devastation she leaves behind. And that is what she does to those people she feels love for. The Thakur is someone Mala hates. If I was him, it is MALA who I'd fear, right now.