Zombie

The Voodoo Zombie (ブードゥのゾンビ), Zombie, or Zombie Girl is a minor character introduced in Shinyaku Toaru Majutsu no Index. She is one of the Magic Gods that resided in the Hidden World, and through her theory that allowed her fellow Magic Gods to step into the world of humans without destroying it after Aleister Crowley breached their world. However, it is her power that eventually led to her and her fellow Magic God's downfall, later being defeated and shown before the eyes of her fellow Magic Gods.

Appearance
Zombie appears as a girl whose entire body is covered in stitches.

Background
Zombie girl is a Magic God and along with others have resided in the Hidden World, separate from humanity.

According to Nephthys, Zombie girl has a background of actively drawing in a great number of cultures. Because of this she has an affinity for most anything. It is this affinity of hers that allowed her to create a theory that allowed the other Magic Gods to step into the world without destroying it.

Magic God Othinus Arc
She is one of the other Magic Gods mentioned briefly residing in the Hidden World.

When Aleister Crowley breached the Hidden World, his purpose was to forcibly swap Zombie's spell, the spell that would infinitely divide a Magic God's existence, for that would allow him to make a Magic God mortal.

St. Germain Arc
Somehow Zombie appears in Academy City on her own without the knowledge of the High Priest's group that have arrived separately from her. There, she is killed by unknown means, likely by the Kihara Noukan. Her body is then wrapped in barbwire and nailed with tungsten spikes on a steel beam cross resembling the Rose Cross.

After the defeat of St. Germain, while the High Priest's group communicate with Aleister her body is catapulted by Noukan towards them, showing them their hubris in underestimating Aleister Crowley.

Abilities
She is a Magic God that is so powerful that her mere presence in the world may destroy it. Due to her drawing many different cultures she was able to formulate a spell that would allow a Magic God to walk in the world without destroying it, which is by infinitely dividing their power in order to deliberately weaken themselves. According to Aleister Crowley, this technique is merely tricking the world to contain a Magic God to exist by eternally layering their existences in a form that is barely small enough for it.

Even though this spell weakens a Magic God, it essentially makes them unkillable as their existences are eternally layered, preventing from truly getting killed unless all of the infinite layers of their existences are killed.