Anomaly Containment Facility, You're Containing Me, a Human?

[No System] + [No Female Lead] + [Cthulhu Mythos] + [No Formulaic Tropes] (Also titled: Sequence: Ascension to Godhood)

The Dark Prison merges with reality, and anomalous creatures invade the world through the "Gates."

An organization quietly emerges. They call themselves the Wardens.

They keep the anomalies outside the "Gates," capturing and containing any anomalous creatures that escape into the real world.

Lu Xiao accidentally falls into the Dark Prison and lives there alone for three years.

After the Wardens discover him and bring him out of the Dark Prison, he becomes an S-Class contained entity-with an official staff position.