Kaijuu 8-gou 怪獣8号

Genres: Action, Fantasy, Horror, Sci-Fi, Shounen
Authors: Matsumoto, Naoya (Story & Art)
Serialization: Shounen Jump+
Synopsis
Kafka Hibino, a 32-year-old man, is unsatisfied with his job as a sweeper. From a young age, he has aspired to join the Defense Corps and kill kaijuus for a living. After a few failed attempts, however, he gave up on his dreams and resigned himself to the mediocrity that provided a decent paycheck. Nevertheless, when an ambitious, 18-year-old recruit named Leno Ichikawa joins his cleaning team, Kafka is once again reminded of his desire to join the military.
Following a chain of unfortunate events and an interaction with the junior sweeper, Kafka encounters a parasite-type kaijuu that forces its way in through his mouth—turning him into a humanoid monster. With his newfound powers, Kafka aims to give his lifelong dream a final try.