The so-called "soul" is nothing more than a high-dimensional encrypted data stream.
The so-called "underworld" is nothing more than a super server cluster running in low-Earth orbit.
When technology reaches the singularity, theology becomes another form of computer science.
In 2099, humans finally cracked the secret of consciousness. The body is just hardware, and the soul is software.
Life: Consciousness runs on the physical terminal.
Death: The hardware is scrapped and the data is uploaded to the cloud server.
Reincarnation: The data is cleaned (drinking Meng Po soup) and downloaded into a new clone or prosthetic body.