User blog comment:Skeith9/Heroic Spirits Speculation/@comment-25336329-20181101230844

Okay, I may have not researched the "laws of Nasuverse" that extensively, but I'll try and write a description for a Servant and let other people say if it sounds sensible or not.

TRUE NAME: Louhi

ALTERNATE TITLE: Mistress of Pohjola

SERVANT CLASS: Caster

ORIGIN: Kalevala, the Finnish epic

ALIGNMENT: Neutral Evil

BIOGRAPHY: Louhi was the witch queen from the northern land of Pohjola and is widely considered to be the main adversary of Kalevala's heroes. She was first introduced as a determined mother figure, who set outlandish tasks for those who wanted to marry her outlandishly beautiful daughters. One of these tasks included the creation of Sampo, a mill-like artifact capable of grinding infinite amounts of corn, salt and coin. As this artifact quickly brought great wealth to Pohjola, the heroes of Kalevala eventually began to desire some of that wealth for themselves. The desire eventually led to the theft of the Sampo, battle for it between Louhi and the heroes, and its destruction during that battle. After the incident, Louhi was determined to make the heroes suffer for Sampo's loss, but after multiple failed attempts the northern queen eventually backed down. It is not known what ultimately happened to her or Pohjola afterwards.

PARAMETERS:

Strength: C

Endurance: D

Agility: C+

Mana: EX

Luck: C

CLASS SKILLS:

Territory Creation D-

Item Construction --

PERSONAL SKILLS:

Conjuring EX

Summoning A

Transformation A+

Prediction D-

SUMMONING CATALYST: A shard of the Sampo, originating from the broken cover brought back to Pohjola by Louhi after the artifact had been destroyed. Aside from the fact that Louhi brought it back, it is not known what happened to the shattered cover afterwards, let alone where she might've hidden it. The shard might also be compatible with the three heroes who took part in the Sampo's theft.

POTENTIAL WISH FOR THE GRAIL: While she might still be angry about the loss of Sampo, she wouldn't use the Grail's power to keep going with her revenge against the heroes. She would instead wish for an infinite supply of corn, salt and coin for Pohjola, one that isn't dependent on a single seizable artifact.

NOBLE PHANTASMS:

Pohjan Kokko (Pohjola's Kokko)

Anti-Unit, Rank D~B

During the fight for the Sampo, Louhi turned herself into a giant Kokko eagle to pursue the heroes on the sea. But instead of a simple transformation, she utilized the remains of her broken pursuit ship by - for example - using scythes as talons and a rudder as her tail. As a Servant, this artificiality is what defines the Noble Phantasm's rank. If she hasn't been given anything to utilize as weapon or such, she will merely turn into an all-natural Kokko, which is less powerful (Rank D). The more things that are provided for her Kokko form, the more powerful it will become (Rank C~B).

While the Kalevala itself doesn't specify what Louhi looks like as a Kokko, one of the most famous pieces of art related to Kalevala depicts her in a harpy-like form. And generally speaking, the theft of Sampo is one of the most well-known events from Kalevala with the aforementioned painting being one of the most well-known depictions of it.

Yhdeksän Sairautta (Nine Diseases)

Anti-Country, Rank A-

After losing the Sampo, one of her attempts to take down the heroes was by using the Nine Diseases and sending them to Väinölä, the land of heroes. While the diseases were eventually defeated by Väinämöinen, the story implies that the entirety of Väinölä was immobilized by the "diseases all unheard of". As a Noble Phantasm the Diseases would be able to able to affect both Servants and normal human beings, but despite their effectiveness, Louhi is only able to control them by giving them orders directly face-to-face and she is unable to order them to not infect someone they come in contact with. Since Louhi is usually someone who doesn't go out their way to cause trouble aside from her revengeful attempts after Sampo's loss, she doesn't like to use this Noble Phantasm unless deemed necessary.