The romantic interest girl, I suspect she's a cat. I only have one reason to think so, that the artist drew her in the same style as the other two known cats with those giant almond eyes, and no one else has been drawn in this fashion till now.
Granted, there has been no other signs of her being a cat. But maybe she decided on being human fully. Maybe Mill senses her catness and attacked, like a intruder on her territory; yes I know she doesn't need to be a cat for Mill to be jealous or treat her as a intruder on her territory but real life cats are usually only territorial with other cats and less with humans.
Edited by truepurple, 07 March 2015 - 06:58 PM.