Maggie
Maggie is an imaginary friend that gio "plays" with all the times. Maggie can get into fights or even straight up homicidal incidents. Poor gio. Also maggie's remains is in the well. She is now a frigging ghost that haunts gio forever. Maggie was the reason why gio put him in the well to stop maggie from haunting him for the rest of his life. I feel kinda bad for gio.
Here is proof of maggie trying to haunt gio
There is no evidence or pictures of maggie!