Elimination.

According to the descriptions of the beast hordes that attacked the city during the beast tide, they attacked in neat order, just like humans would do.

He had imagined the leaders of each type of beast would lead their species into battle, but from what he had just seen from the dormant beasts, his imagination was wrong. High-ranking beasts could control weaker ones of any species.

[How is it possible for high-ranking beasts to control beasts of totally different species?]

"Obviously the beast tide." Blake answered.

[Doesn't it feel strange that beasts gain such a useful power during the beast tide?] The system asked.

'Yeah… If I was in the position of the thing behind the beast tide, I would want to unit all beasts under one command.' Blake said.