Voodoo

Voodoo (ブードゥ) is an African diaspora religion, a mishmash of Afro-Caribbean witchcraft and necromancy.

Principles
Voodoo is described as not actually having fixed teachings or spells, being a culture that draws in other cultures, borrowing gods and ceremonies from other mythologies and religions, and adding to them while making them its own to continually expand. Isabella Theism, a necromancer who uses a mix of Voodoo and Christianity, has highlighted the affinity and called Voodoo a greedy religion that takes in every last miracle it comes across.

There are a number of concepts which are associated with Voodoo, some originating from cultures where Voodoo is also present, but are technically the result of misconceptions or falsities. Despite this, these concepts and their associations can be put into practice regardless.

There are a number of spirits or deities within Voodoo,  referred to as the  (also spelled lwa), or Mystère (ミステール). One of these figures,, serves as intermediary between his kind and humanity, and thus indirectly appears in all Voodoo ceremonies. Another notable figure is, who dwells at the crossroads between life and death. In the process of incorporating ideas from elsewhere, Voodoo has also taken in a number of deity figures from other religions, even including Yahweh.

Voodoo is known for having many curses. One type commonly associated with it is a voodoo doll (呪術の人形), a straw effigy representing a person (often with a piece of them attached) which is used to manipulate or harm them, though this is actually just one derivation of an idea which has spread into various other cultures besides Voodoo. The Ceremony of Ba Moun is considered the worst and most wicked spell in Voodoo and its most horrific curse, where a magician makes a contract with a demon which will grant them their every wish in exchange for the magician annually sacrificing someone they care for, being devoured by the demon if they fail to carry out the sacrifice.

As well as curses, Voodoo has a variety of drugs and concoctions, from wound-healing paste mixed from different vegetables and meat, to a deadly poison created from a single lime growing on a tree. One of the most notable is zombie powder (ゾンビパウダー), which is used in the creation of  - one of the most well-known specialities associated with Voodoo. Rather than making corpses rise from the dead,   as is often thought of with zombies,  chemicals are used to intentionally harm the body and remove the Ti Bon Ange from the five components of the soul, putting a person into a state of pseudo-death, robbing them of their mind and remaking them into a living unit which can be controlled. In the past, zombification was apparently used as an extreme form of punishment.

Background
Voodoo has its roots in traditions and religions from West Africa. These beliefs were brought over to the with the slave trade, where they became syncretized with the culture of the slave owners together with a little Native American influence, eventually producing several varieties of the religion which came to be known as Voodoo. One notable variety developed in Haiti.

Voodoo was present in the during the age in which  terrorized the seas.

Toaru Majutsu no Index SS: Agnese's Magic Side Work Experience
Necromancer Isabella Theism uses aspects of Haitian Voodoo in some of her spells and utilized them during her mock battle with Stiyl Magnus in Barcelona, as part of Agnese Sanctis, Lucia and Angelene's training. Concepts associated with voodoo were also referenced during the nuns' investigation of the forensic cleaning at Nihili Padpois's restaurant, given the owner's past in Haiti.

The incident which the nuns later investigated in Frankfurt was the result of a magician trying to escape from the curse of the Ceremony of Ba Moun. The magician in question, Frau Halveria, also made use of other spells involving Voodoo.

St. Germain Arc
A member of the true Gremlin, Zombie, had a background rooted in Voodoo as well as actively drawing in a great number of cultures, giving her an affinity for almost anything which allowed her to devise a spell which would allow the Magic Gods to safely enter the world after their Hidden World was breached.

Kamisato Rescue Arc
Toyama Luca of the Kamisato Faction makes use of Voodoo-based magic as a follower of Legba Atibon.