Isadora could have chased him.
The power differential between them was too great.
A rank 9 and rank 3 wasn't even a competition.
But there were two reasons she didn't.
First and foremost, she was in a state of self-imposed restriction, keeping her strength only at rank 5.
This was to prepare herself for sealing the devil. By compressing the aura and restricting its usage, she was pushing herself to become more efficient in using it.
In principle, it worked similar to running with weights on to build stamina.
She was ready to remove that restriction if this man was really a devil. Since he wasn't, she was reluctant to stop the training session.
To show best results, it had to be carried on for 30 days. This was 23rd day already. She didn't want to waste the efforts she put in until now.