The decision to storm the human settlements came for the sake of venting anger for the Azil tribe and to collect information for the rest of the northern tribes, even though they know that their endeavor is not without real benefit, as Richard and the rest of the humans Martial Emperors who support him have a different body composition than the humans known to them.
However, they decided to go anyway just for the sake of it. The decision was made quickly as if it was something they took for granted. They could storm wherever they wanted and kill whoever they wanted, the decision was very easy, like taking candy from a child, but they soon learned that they had hit a hornet's nest.
The army of the Azil tribe that was sent to attack the human settlements was completely destroyed, even the forces of the rest of the tribes throughout the northern region were all annihilated!