Sebastian was ambushed during the awakening ceremony of his familiar beasts and only received an F-level pet cat. However, with the SSS-level talent "Evolution and Rebirth", he evolved the cat into a cat girl named Chloe, and discovered that she had the "Devourer Beast" trait - she could infinitely improve her attributes by eating. In the trial of the Hundred Beasts Forest, he continuously hunted wild beasts to strengthen Chloe, successively enslaved powerful familiar beasts such as the Silver Moon Wolf and the Bloodthirsty Bat, and finally defeated his archenemy Andre in the arena competition, joined the Aier Legion, and embarked on a journey to the Holy Spirit Battlefield to find a life-saving medicine for his sister.
