Assassin of Black

Jack the Ripper, Legendary Serial Killer (伝説の連続殺人鬼) is a Servant of the Assassin class designed by Yuichiro Higashide.

The perpetrator of a series of bizarre murders in 19th Century England. A young girl filled with contradictions, possessing properties of both day and night. Her personality is pure, but cruel at the same time. Though her manner of speech is innocent, she is quick of thought. She is rational, but is emotionally weak. She responds cruelly to others' ill will, but is soft against good will. And although she wears revealing clothing, she is shy, and doesn't go out during the day. She yearns strongly for a mother, and if her Master is female, she will insist on calling them "Mother".

Skills
Presence Concealment (気配遮断): A+

Near-complete elimination of presence, as a Servant or otherwise, which fails only upon the execution of an attack. The weakness of this skill is compensated for with use of Murderer of the Misty Night, allowing for perfect ambush.

Mad Enhancement (狂化): C

A skill obtained if summoned within the Berserker Class. In exchange for a Rank Down in Luck and Mana and the loss of verbal communication and complex thinking, all other attributes are reinforced. As a Berserker, the Servant is capable of acting only at night; The Mist remains active at all times, and all entities within range that possess prana will be targeted.

Murderer of the Misty Night (霧夜の殺人): A

A skill associated with the Servant's nature as a serial killer rather than as an Assassin, which permits preemptive strike against all opponents. However, unconditional success of the skill is possible only at night. Requires a successful luck roll for use during daytime. It is believed that all victims of Jack the Ripper were assailed when unguarded.

Mental Pollution (精神汚染): C

Provides a probability that mental interference magecraft will be rendered ineffective. In the condition that the Servant's master is of Evil alignment, and perpetrates acts of cruelty against the Servant, Mental Pollution will increase in rank, further increasing defenses against magecraft. However, as the Servant's psyche is inherently broken, this may result in irreversible deterioration.

Information Erasure (情報抹消): B

Following the conclusion of an engagement, information regarding the Servant's True Name, abilities, and appearance are removed from the records and memories of all witnesses, including the opponent. This effect is enforced even within digital recordings by a closed-circuit camera in broad daylight. However, evidence of the engagement is not removed from the scene, and by way of logical deduction, the Servant's identity may be revealed.

Surgical Procedure (外科手術): E

Surgical repair capability with use of a bloodstained scalpel, applicable to the Servant or her Master. Despite the technique being 120 years old, and somewhat unreliable by visual appearance alone, the procedures manage to attain their intended effect, boosted somewhat with application of prana. The victims of Jack the Ripper were found with their organs removed in such a way as to require anatomical knowledge or skill with dissection.

Noble Phantasms
Maria the Ripper: The Holy Mother of Dismemberment (解体聖母（Maria the Ripper))

Four knives that are normally classified as Rank D Noble Phantasms. However, empowered by "the tragedy and will of the 80 thousand children abandoned in London by prostitute mothers," the Noble Phantasm can guarantee instant death if certain conditions are fulfilled; if a) "it is night-time," b) "the target is a female," c) "it is misty," the knives manifest within the target's body, instantly vivisecting their flesh. Though the Noble Phantasm can be activated merely to deal physical damage when conditions are not completely fulfilled, in the event of fulfillment, the damage rendered receives a large boost in Rank. As the attack is communicated as a curse rather than as a technique executed by utilizing the Noble Phantasm as a set of knives, it may be used at range. Physical defense is impossible, but resistance to curses may permit evasion.

The Mist: Darkened Misty Metropolis (暗黒霧都（The Mist）)

A Noble Phantasm that takes the form of a bounded field filled with a mist wrought of prana, which inflicts death upon all normal humans who enter within a few turns. Comparatively, a magus won't die immediately, but will receive continuous damage. Heroic Spirits who enter do not receive damage, but a Rank Down in Agility. As all sense of direction is lost within the field perimeter, employment of magecraft or a Rank B or higher in Instinct are the only means of escape. The Servant who uses this Noble Phantasm can select who within the bounded field is affected.

During the Industrial Revolution, large quantities of smog were emitted with the use of coal, eventually resulting in a crisis wherein a mist of sulfuric acid plagued the city of London in the 1950's. "The Mist" is a Noble Phantasm that reenacts the phenomenon of the "Mist of Death".