The growth of Vicious Minds.

Vicious Minds are the materialized subconscious will of the subjects that are created by the cores.

They have identical memories, personalities, and bodies of their former selves.

As a Vicious Mind goes through numerous battle scenarios, it utilizes more of its core's powers.

However, if its subconscious will isn't maintained, Vicious Minds soon lose their memories and will, and end up being fragmented.

As this process repeats itself, the number of Vicious Minds increases exponentially, while its memories and conscious will dissipates.