[Black Swirl Mark]
A method used by Fate Space to mark "Uncontrolled Ones."
The so-called Uncontrolled Ones, similar to [The Clown - Pennywise], carry the highly contagious and mentally assimilating "Clown Virus." Once a life form in the World of Fate is infected with the virus, it will turn into a 'resurrection container' for the clown.
If Fate Space were seen as a system,
then the clown would be like a virus capable of self-replication, infecting other programs without limit... Once it died, others would transform into it.
Beings like the clown, capable of greatly affecting the ecological circle of fate, were marked by the Black Tower.
They were forcibly detained in the bottom detention area of the Black Tower for a long time and only found a chance to escape during a rare inter-dimensional turbulence that occurred once in hundreds of years.