Double Demons

The story begins as an isekai -- the main character (the player) "dies" and is reborn into another world in which reincarnation is part of the life and death cycle of its inhabitants. There are humans, demons, and gods in their respective worlds. Souls aren't one-to-one in this world; they are pooled together as raw energy, or "soul essence," in order to fuel the cycle. However, several individuals and groups realize how valuable soul essence really is and have figured out how to tap into it: by entering the spirit world and killing spirit monsters. This causes a large-scale breakdown in society as people are born without enough soul essence -- so much so that a large percentage of the population are functionally vegetables. Low soul essence in the earliest stages looks like depression or laziness, but as it progresses it means the individual is unable to eat, bathe, or take care of themselves at all. A sinister corporation, AiX, has developed the technology to allow these people in the late stages of this illness (called "low axis") by providing a medical headset device to essentially pilot them through the bare minimums of daily life. The player inhabits the body of a late-stage low axis new college student. The "God" of this world that reincarnates the player gives them a gift -- they are able to accelerate the soul essence they gain from killing monsters (or XP). The player/MC breathes new life into this previously bed-ridden teenager and begins living a double life - one of an ordinary freshman college student, the other as a spirit fighter trying to figure out why the world's soul essence has fallen out of balance and how to fix it.