Rooster Fighter

With the highest kaiju-emergence rates in the world, Japan is no stranger to attack by deadly monsters. Enter the Japan Defense Force, a military organization tasked with the neutralization of kaiju. Kafka Hibino, a kaiju-corpse cleanup man, has always dreamed of joining the force. But when he gets another shot at achieving his childhood dream, he undergoes an unexpected transformation. How can he fight kaiju now that he’s become one himself?!

When the Monster Army invaded Earth thirteen years ago, the Divine Dragon Rangers rose up to stop them! With the war raging on, these great heroes are mankind’s last hope! ...or are they? In truth, the invaders were subjugated within a year, forced to continue to crank out a monster a week for the Rangers to crush in front of their adoring fans! But one monster has had enough. Something has to change! He’ll rebel against the might of the Dragon Rangers and destroy them all...from the inside!

The world is divided into two factions: humans and monsters called katawara. Despite being a katawara, Tama loves humans and vows to protect them from evil, even if it means fighting her own kind. Her brother Jinka, however, hates humans, despite mostly being one. The siblings are joined by a cowardly swordsman named Shinsuke, who wants to learn how to become strong. When the group uncovers a plot to experiment on humans and transform them into monsters, they vow to defeat whoever is behind it... Even if it means battling an entire army of warriors.

The story takes place in an age of swords, heroes, and myths. Giant beasts created the land, but then humans stole that land. This angered the beasts, who then started eating humans. In order to fight back, humans called upon the gods. The Kyojuu beasts started spreading around the world, causing great damage, but humans fought back by hunting the Kyojuu. Humanity also prospered by to using the dissected parts of the beasts. Jiiro is "a man who has escaped death," and he hunts Kyojuu to earn a living. He meets "Twenty and Second Kuumi," who is being chased by someone. Jiiro and his friends then start to uncover the secrets of this world.