Crona watches Soul on and off for most of the day. She's not aware that such a thing is creepy, and so keeps doing it. You can learn a lot of things about someone as you watch them. Such as the fact they're hiding a huge part of themselves from others.

At one point she gets very hungry but she has no allowance left. She spent it all on candy for Ragnarok. If she was being stealthy before, she is not now, and her stomach grumble gives her away as being a few steps behind and around the corner.

Darn.