Name: Dekkaedo
Background: Dekkaedo's desire to be the most hopeful and pure-hearted Magical Girl resulted in her becoming the most wicked Witch. She wished for the power to prevent all other Magical Girls from becoming Witches themselves. This allowed her to travel from universe to universe, freeing all Magical Girls from their contracts at the moment of their death. She gave these Magical Girls, who she cared for like her weaker sisters, closure so they could pass on without the fear of being reborn in a horrible form and cursing their own people. Since Dekkaedo never fought Witches herself and contributed nothing to the Magical Girl system, it was only natural that she tragically had to become a sort of "supreme Witch," built on all the misery and grief she had accumulated from the Magical Girls she had saved, to maintain the balance of nature.
Description: Dekkaedo is everything and nothing. She is everywhere, yet nowhere. Her mere existence is a world-destroying paradox. She is a being who freely passes through timeline to timeline, constantly searching for Magical Girls to defeat. After arriving in a new timeline, she will remain there until all of its protectors are dead; typically destroying that universe's human race in the process.
The interior of Dekkaedo's maze seems to be heavily inspired by the biblical Garden of Eden. This has been described as one of the most pleasant mazes to become lost in, until you notice your body is slowly decaying while you're still alive. The familiars that reside here are an enormous swarm of locusts that alert their queen when a new victim has arrived. Whether these insects are another religious motif or a reference to something else is unknown.
If this Witch appears in your universe, consider your people doomed. She has never been defeated, and no one has ever escaped her maze. If you're a Magical Girl who also has the ability to leap through timelines, it's highly recommended that you use this power to reverse Dekkaedo's appearance and preserve your world.