Outside the demon corp, James had a change in heart regarding his initial plan.
In fact James was all brawls and no brains at fighting. This might be considered one of his strongest points, but in return it was also his deadliest weakness.
In some situations, fighting wasn't going to solve anything. In return it would rather make things even worse!
Like this situation for example, it appeared on the surface that the werewolves had the upper hand here. However James and other leaders of the werewolves knew how thin their forces were stretched at the moment.
After all, fighting with demons wasn't in their agenda at all! They only had one enemy, and that enemy was really ferocious.
If they let many of their troops fall here, then the vampires would be a far target to aim at. Instead the vampires might even go greedy and think about targeting them.