There is a woman with the mask guy who asked him to look after Agam whereabout.
The one he was talking on the phone was the nurse Today..she called to let him know Agam is coming to Amritgargh..
Its with her that she was relating how Nimrit ruined his life and the malik family will have to pay for it even if someone has to die..
So now its clear his revenge is not only with Agam but the whole malik family..
My guess is its Adhiraj singh.he was Tall and his voice quite same and his mentioning Nimrit destroying his life hints a lot that he can be the only enemy of Agni of their past...
I feel creatives will bring back the character of Adhiraj as he did not die in the show ..his truth about him being impotent was all in the media..may be he lost all his prestige with so much humiliation ..so he is back for revenge..
Now who is that lady with him?..Rajmata..shivangi..vishal sis if he has one..so lots of mystery ...