Jack Prometeria

Jack Prometeria (ジャック＝プロメテリア) is a British magician who manages a shared ceremonial ground hidden in a container yard in 's harbor district.

Appearance
Jack Prometeria is described as a gray-haired old man, short but with thick muscles.

Personality
Jack presents himself as a realist, involved with the magic side and providing his service for monetary purposes, and not guilty about it. In his cover job, he apparently plays a boring old man with no real interests.

Having being told stories of by his father, Jack holds the ship in high regard and was unwilling to leave it affected by the infamous Aleister Crowley's influence after learning about it. Knowing that he was at the end of his life, Jack was not afraid to die from the destruction which would be caused by the phantom Hood as it reached land, only wishing to purify the ship of Crowley's influence and experience the ship from himself before he died.

Background
Jack Prometeria's father was a magician who was on the crew of the battlecruiser, one of the few survivors when the ship was sunk in the icy waters of the north Atlantic, and frequently told the young Jack stories about the ship he proudly served on.

Jack eventually ended up in Calais, where he managed a hidden side to the container yard while officially working for the harbor. Taking advantage of the market created by problems faced by individual magicians due to the influence of powerful magic cabals, he rented out at least one shipping container as a shared ceremonial ground for magicians to use in exchange for physical cash. The container was moved around the yard at irregular intervals to make it harder to track down. Jack did not keep full records of the individual ceremonies his customers were performing, but he kept enough for him to track them down should they try to skip out on payments.

At some point, Jack learned that symbols of Aleister Crowley had somehow been worked into the ship and given Crowley's bad reputation among the magic side, Jack could not leave it like that, seeking to remove his influence from ship. Two years before the current year, he was told that he had about half a year left to live, but sought to purify and experience Hood himself before he died. To accomplish this, he devised and set up a complicated summoning ceremony, which would be inadvertently carried out by the magicians using the shared ceremonial ground.

Toaru Majutsu no Index SS: Agnese's Magic Side Work Experience
After Agnese Sanctis, Lucia and Angelene tracked down the ceremonial ground used to summon Hood and broke into the shipping container to confront the culprit behind Hood's summoning before the ship could reach France, only to find Harris Nicholagene and his mandrakes, they were introduced to Jack, who told them about the sharing ceremonial ground and the service he was providing. Telling them that merely destroying the container would not be enough to make the summoned ship disappear and that he did not keep full records of the ceremonies being conducted by his clients, Jack provided the names of the magicians who had recently used the ceremonial ground and mentioned the means he had for tracing them.

As the phantom Hood was approaching Calais, Jack went to the harbour's lighthouse to see its arrival, only to find Agnese waiting for him on the viewing platform, having deduced his involvement. He explained his motivations, how his father had served on Hood, how Crowley's symbols had ended up in the ship's designs, and how he wished to purify and experience the ship for himself in the short time he had left to live. However, he was dismayed to find that the ghost ship would never reach land, due to a flaw from his overcomplication of the summoning ceremony.

Agnese decided that shock of learning he could never experience the Hood for himself was punishment enough, knowing he did not have enough time left to make a new plan.

Abilities
Jack has mentioned having methods to track down clients, even if they use a false name and address, should they try to skip out on payments. Only taking payments in hard cash, with a physical hand-over, he is apparently capable of using the residual information from the notes for tracing purposes.

Hood Summoning Ceremony
In order to fulfill his wish of purifying and experiencing the ship before his death, Jack devised a complicated summoning ceremony to call forth as a ghost ship. In order to avoid detection and to ensure that the ship would continue even if the summoning site was discovered, Jack made arrangements so that the spells of magicians making use of the shared ceremonial ground in a shipping container would combine together to perform the ceremony without him being involved in the actual summoning, with his clients unaware of both the summoning they were unwittingly performing and its respective exorcism ceremony.

When tracing the summoning site and predicting the composition of the magic circle, Agnese Sanctis deduced that it included the symbols of iron (Mars), lead (Saturn) and sulfur (from gunpowder and sulfuric acid, and indicating earth) with the ship being salt (ether). The flow of energy followed a path entering from the south and leaving to the west-northwest. The individual summoning spells carried out by the unwitting summoners which were making up the ceremony, each providing a symbol, included:
 * Pierre Gosetti: The creation of a protective talisman using Taphthartharath, the Planetary Spirit of Mercury.
 * Rini Calculed: An attempt at inducing astral projection to investigate marks left on the body, involving the alchemical principle of salt.
 * Plum Mordosié: A murder attempt, aiming to extract the target's physical body through three alchemical principles (salt, sulfur and mercury) to destabilize them and lead to their own power destroying them.
 * Harris Nicholagene: The creation of mandrakes and attempts to give them a feminine appearance, with claims involving the alchemical principles of sulfur.
 * Rouen Nalberia: Experiments to develop a method of cooking to extract elements from food.

It would not normally be possible to summon a 20th century warship, a purely mechanical object without an occult foundation, however it is possible with Hood because Aleister Crowley's symbols were unwittingly included in the design. Summoned separately from the actual wreck, the phantom Hood possessed all the functions the Hood had as a ship, including the use of its guns, and could utilize them without a crew. After being summoned and operating autonomously, it headed for the summoning site in Calais,  though it would never actually reach its destination and disappear before then due to a flaw from overly complicating the ceremony.