In an already-destructed Japan, Yahoro spent his day working as "the collector". He had finished up his work as the collector today as well when he ran into the so-called "monsters". He got had his internal organs jacked up and "safely" arrived at his bed.
The Hollow Regalia is a completed manga by Mikumo Gakuto, first published in 2022. It blends sci-fi and action. You can read all 11 available chapters of The Hollow Regalia online for free on MangaPulse; the newest is Chapter 11, added 2024-05-10. The series is finished, so you can read it from start to end in one go.