Remina/Paradox

Overview
This Remina was destroyed during the Great Disaster, only a rift to Tartarus remains.

It is the place where the Great Disaster was caused. Uninterrupted by Ilias, a group of scientists intended to use Heinrich's sword to bring his spirit back. Unfortunately, because her blood was on the sword, they instead brought up Black Alice from the original world after the latter got defeated by Luka. Since she had both the powers of light and darkness integrated to a cellular level thanks to the White Rabbit drug and her attempt to devour Ilias, she transformed into the Goddess of Chaos.

As of part 2, it hasn't been explored yet.