Crow
GLORY TO THE DECEPTICONS

"Mother... mother...? Where are you, mother?"
Name:
Assassin of Black / Jack the Ripper
Series:

Canon:
After their supposed death
Abilities:
Class Skills

Presence Concealment - A+
Hides one's presence as a Servant. Suitable for spying. It is possible to disappear completely and become almost impossible to be detected, even against a Servant's perception. However, efficiency will decrease once preparations to attack are taken.
Personal Skills

Murderer of the Misty Night - A
A skill associated with the Servant's nature as a serial killer rather than as an assassin, which permits a preemptive strike against all opponents. Requires luck to work for sure in day, but unconditional success possible at night.

Information Erasure - B
The removal of information regarding the Servant's True Name, abilities, and appearance from the records and memories of all eye witnesses, including the opponent, following the conclusion of an engagement. This effect is enforced even if the battle took place in broad daylight or was recorded by devices such as digital recordings of a closed-circuit camera. However, evidence of the engagement is not removed from the scene, and by way of logical deduction, the Servant's identity may be revealed by examining those evidence.

Surgical Procedure - E
If that icon doesn't scream irony I don't know what does!
The capability of surgical repair with use of a bloodstained scalpel.
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 Magical Energy. (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.)

Mental Pollution - C
Makes it possible to shut out any mental interference Thaumaturgy due to possessing a distorted mentality. However, at the same time, it becomes impossible to come to an understanding with individuals that do not possess an equivalent rank of Mental Pollution.
In the condition that the Servant's master is of the Evil alignment, or perpetrates acts of cruelty against her, her Mental Pollution will increase in rank, further increasing the chances of blocking magecraft. However, as the Servant's psyche is inherently broken, this may result in irreversible corruption.
Likewise, it is possible for this skill to be removed if the Master is of a more Good alignment, seeing that Jack the Ripper as summoned by the more morally-sound pure-hearted justice-seeking protagonist of Fate/Grand Order does not possess this skill.
Noble Phantasms
Maria the Ripper: The Holy Mother of Disembodiment - D~B
The Mist: Darkened Misty Metropolis - C
Unlisted Feats
These are feats and abilities shown that are not listed above.
As stated in her history, Jack is made from the souls of tens of thousands of abortions. When she is cut, she will not bleed an agonizing red, but rather, release a black liquid that is, in reality, these very souls. These souls can materialise into child-shaped wraiths or black phantom fetuses with fully-grown teeth, and possibly possess others. For balancing purposes, the possession ability will be used within reason, or possibly not be used at all.
She can identify people by smell to some extent, evidenced when she sniffs Mordred aka Saber of Red and comes to the conclusion that she was a woman. This event also occured when the Mist was activated, which shows that she is immune to the toxins of her own mist, as well as phenomenom similiar in nature to it such as factory exhaust, and she can even smell through her own mist.
See more here.
Equipment:
Her default weapons consist of four butcher knives, alongside a wide variety of daggers in her pockets. As mentioned, she does possess a lantern, that while can be used as an actual lantern, is mainly used to activate one of her Noble Phantasms, The Mist.