Gathering allies

Even though they had seemed fearless earlier, it didn't seem like they were completely fearless.

Even though they were controlled, it seemed that they still had free will to a certain extent. 

That made sense since it would surely take a lot of power to fully control all of these spirit beasts. So the only thing that would make sense was partial control over these spirit beasts.

That meant that once something pushed them over the limit, they would be able to break free of the thing restraining them.

In this case, it was fear that had pushed them over the brink.

After edging back for a bit and losing a few more of their compatriots, the spirit beast finally gave up and turned to run.

It was just too bad that there were no plans to let them leave.