[TW: lots of death,ghosts/phantoms,gore,blood,depression,needles,and trypophobia]

Okay. Let's start with the basic setup.

In this world,all living organisms are selected to have a phantom for a partner.

When the phantom is selected for the person,whoever was chosen gets killed. The ways people die range. They usually live between 10 minutes to 4 hours when selected.

There is no escaping this system. It makes sure the phantom is close with the person they selected for them. The selection happens twice between every decade.

No one knows why or where the selection came from. The selection itself is a gamma organism that acts like a system. It also has multiple flesh beings to watch over it,and make sure no one tampers with it.

algebraliens cannot escape this either.

BFDI/BFDIA were the only seasons that successfully ran without anyone dying from the selection.

After that,most of the contestants were killed off and turned into phantoms.

Phantoms cannot be revived due to being in a state of limbo,where they are constantly alive yet dead at the same time,making them feel the pain of death repeatedly.

Phantoms can only be seen by the person that they were selected for,but phantoms can see other phantoms.

Phantoms are there to watch over the person they were selected for.

Phantoms also have varying ages,depending on when they were killed.

At the moment,these are the phantoms and the person they were selected for. 

Pen and eraser

Fiery and leafy

Gelatin and lollipop

Flower and ruby

Basketball and grassy

Winner and loser

a and x

Two and four

And many,many more...

[People with phantoms cannot be killed by the selection,essentially saving them from death.]

[Yes you can ask how any of the phantoms died or if a specific character is a phantom/selected person.]

(...thinking about making this into a book...)