To me Nagini was my first play-mate. Many people know now that she had the maledictus curse. A woman that could transfigure and ended up finally as a snake. I know that when I spent time with my father as a toddler that Nagini was there. I am a parselmouth too and perhaps she found it desirable to have another form of communication than that of the a man.
My powers of transfiguration were not so strong but they were clearly there. Changeable hair colour and a snake tongue to speak to her. For me it was play. But this was the Dark Lord and his Death Eaters at the height of power. I doubt he was anticipating bringing up any of the Malfoy, Snape, Crabbe, Goyle or Black families as anything other than Death Eaters.
I never knew about her curse, I wonder if she looked at me as something she wished she could be or worried that I may be cursed like her.
Others were afraid of her but I knew her to be kind it was as though she could be herself with me. I understand that feeling.
I didn't see or hear of Nagini from the time my mother died for another 12 years. I couldn't believe it.