Invaders are the ones on offense, snakes and devil cats, created by a certain god and were never seen by humans. These two races united to conquer the Earth from the dominate hands of the humans. Snakes wished to bask freedom and maintain REAL order on Earth. And devil cats sought to destroy those in their way and cause havoc.
When these two races found each other in the great invasion. They at first attacked each other but soon realized they had one goal. And they united to make the perfect team.
Snakes were very tough, if not, they were able to engineer or even cast venom magic.
And devil cats had claws so sharp, they can rip through steel without a problem. Devil cats even mastered fire magic.