Everything became messy rather quickly.
The natives were waiting for the alien forces to attack, and they had done their best to assemble an army to repel the invaders. However, even their mental state wasn't in perfect condition, and the battle happening above them worsened their situation.
It was impossible for humans that had always relied on their minds to become used to the intense instincts of the magical beasts in a matter of months. Actually, that aggression and hunger that they had developed would work against them until they fused both parts of their existence into one.
Noah had to spend years in the wilderness, learning about his beast part, and it was only after his body reached the fifth rank that his centers of power obtained the benefits of his hybrid status.