Emonami

Emonami - There is a virus called Animon savage. It effects you inside and outside, making you a wild demihuman of any animal, and if it claims you, you become a animon yourself

You have to avoid being claimed be these animons because they can be savages when it comes to this new world because of the virus, one day, your brother emonami gets claimed by a animon bird boy, now he's after you