Continuing my habit of adding Masters because I keep playing characters who go offscreen a lot and many Servants still don't have clear ones...

Something for our evil professor.

[list][*][u]Name[/u]: Elferia Bay
[*][u]Age[/u]: 18
[*][u]Appearance[/u]: [url=https://i.imgur.com/CJpEptr.png]She looks very innocent.[/url]
[*][u]Personality[/u]: Elferia has always been a girl with a strong interest in mysteries--not the magical kind, but the fiction genre. Spotting the clues, putting them together to find the villain... and for as long as she can remember, she's also been very frustrated by them. First, there's the obvious culprit, the mysteries that are just wrong, where the conviction relies on some clue that is counterfactual. Right after that are the mysteries written primarily to be a story, hiding important details from the reader and relying instead upon the detective. What Elferia wanted was a mystery where the detective was stumped, but the clues were there--a perfect crime in the story, but one a clever reader could puzzle out. But then she got her real interest: [i]planning[/i] the perfect crime. What clues could she remove? What did the detective rely on to solve it?
She's not quite immoral enough to act upon her plans in reality, simply plan them out, and assess everyone as a potential asset or obstacle first or foremost. It doesn't matter if the crime would be for something laughably minor or ultimately irrelevant; the goal is the execution itself.
When she's [i]not[/i] exercising her manipulative streak, she's a pleasant but not too social girl with an interest in mathematics.
[*][u]Abilities[/u]: Primarily, Elferia is a practitioner of a form of Numerology, itself already a derivative of Gematria. Regardless of the founder's existence or not, or choice of methods, hers has more in common with the magecraft of Atlas than its ancient origins might imply. Rather than convert words into numbers, directly consider the phenomenon desired, break that into numerical components, and from there visualise and materialise the appropriate circles. Despite its pseudo-scientific basis, it still draws strength as a form of Kabbalah. Elferia summarises it thus: "an efficient and versatile approach, suited to an average magus of sufficient intellect."
All of this complexity is backed up by what Elferia thinks is the more useful thing Atlas' alchemists came up with: Thought Acceleration. Considering multiple approaches in detail or analysing every view or possibility in detail might be an impressive trick, but solving a single complicated problem faster is far more useful to her. Plus with the potential deviations increasing exponentially with every step, she doesn't even consider the "multiple thoughts at a time" approach useful; a heuristic to keep to the most probable course then recalculate works well enough on the human scale. 
[*][u]History[/u]: How and why Elferia has access to [i]anything[/i] to have come out of Atlas is quite hard to answer, seeing as she never asked her father before his death due to her age, and her family name doesn't sound anything like a magus family, and her mother passed away before she can even remember. Not that she's lived alone all her life--a city where you can summon a Servant, and will likely summon based on compatibility is quite useful that way.
[*][u]Other[/u]:[/list]