My views:
Point 1: Abhay and Maithili were in love some 100 years ago.
Point 2: As per one of the flashback scenes, Maithili was asking abhay when they are going to confess their love infront of everyone/whole world.
Point 3: A series of unknown incidences would have happened due to which Abhay came cloderto his death bed. This is when probably Chand Haseena would have turned him into a vampire.
Point 4: Maithili would have died being a human itself.
Point 5: Maithili is reborn as Pia and is getting attracted to Abhay.
My concept: Just imagining! How about a twist like this - Pia, someday, will confess that, her real birthname was maithili and then, just to protect her identity from her father, she changed her name to pia? (LOL! Some abstract funny idea. Don't kill me if you find this gross!) That would make AbhIya more closer! Wow!
Love,
Annie.