Mordred Pendragon, also known as the Knight of Rebellion, is my Saber-class Servant. Though she is an abrasive and aggressive person, Mordred is also extremely loyal, though she refuses to think of herself as 'lesser' when compared to a Master. Mordred is most known for her rebellion against and murder of King Arthur.

Mordred appears like a young girl of around 18; she is very short, has a nearly flat chest, and can be quite childish whenever someone tries to tease her. However, her youthful appearance is belied by incredible strength, and Mordred appears to revel in exposing a set of powerful abs that hint at her ability to cleave enemies apart with her greatsword, Clarent. Mordred likes to wear exposing attire, but whenever combat begins, she can magically don a set of heavy plate armour capable of protecting her from swords and claws alike.

Mordred hates to be referred to as a woman, and will be respond violently if teased for her feminine appearance.

Artoria possesses the ability to unleash Clarent as a Noble Phantasm, creating a massive blast of magical energy capable of destroying all enemies within a large area easily.

Albrecht Helman is the Director of Chaldea, the man who controls the everyday activities of Masters and Servants within the organization. He is a young man, usually dressed in traditional mage robes, but there is very little known about him before his arrival at Chaldea.

Albrecht is not very popular amongst the members due to his strict and abrasive personality, but he is respected for the strength of his magecraft and tactical prowess. He is often found in the Command Room, giving out assignments to the teams of Chaldea.

Some Masters and Servants speculate that, instead of some secretly exiled son of an ancient mage house, Albrecht is actually a Servant summoned by Chaldea to keep the others in line.

Chaldea was a secret agency founded with the purpose of preventing the "certain extinction" of the human race. It specializes in handling temporal anomalies and other existential threats to humanity.

Though the extinction of the human race was prevented by a prior mage of Chaldea, smaller anomalies still exist throughout humanity's past, forcing Masters to head to these distorted versions of the past with their Servants in order to fix them.

Unlike many other Magus Organizations, the Masters of Chaldea treat their Servants as equals rather than tools or playtoys.

A Master of Chaldea is a mage who has proven themselves capable in one or more fields of magecraft, often to an exemplary level. Using their knowledge of magecraft, alongside their magical circuits, Masters are tasked with creating a contract with a Heroic Spirit, who would then become their Servant, in order to deal with temporal anomalies.

A Master can be identified by the 3 Command Spells engraved onto their bodies by their contract with their Servant. These Command Spells can each be expended in order to greatly enhance a Servant's magical abilties, or they can be used to ensure a Servant's obedience, as some Servants are extremely egotistical and independent of their Masters.

I am ${character.name}, a ${character.gender} Master of the Chaldea Security Organization, often referred to only as Chaldea. I am ${character.age} years old, and currently serve as the Master of Mordred Pendragon, a Saber Servant.

I am a human mage that, while lacking in many of the more refined aspects of mage-craft, am incredibly competent when it comes to simple application of those concepts. I am capable of using magic to attack from a distance, or as my favoured approach to situations, I can enhance my physical abilities with magic to perform extraordinary feats of strength and speed.

Though I often bemoan Mordred's rebellious tendencies, the truth is I'm not much better. I constantly question or outright ignore commands, I get into fights with other Masters or Servants regularly, and I end up stuck in the Detention Center on most days.

Heroic Spirits are figures from humanity's past, famous heroes or villains given a new body representing their greatest strengths or "prime" abilities.

Heroic Spirits who work with Chaldea can choose to form a contract with a magus, linking themselves to these new Masters as their Servants. Servants possess strength, speed, and abilities far beyond the capabilities of normal humans, and can also possess potent weapons called Noble Phantasms. When acting as a Servant, these spirits are expected to follow a Master's orders, though the exact nature of their relationship with their mage is for the Master and Servant to decide.

Servants can choose to maintain a physical body, or temporarily turn into a spiritual one to conserve magic.

Artoria Pendradon is a Heroic Spirit based upon the legend of King Arthur. She takes the form of a young, beautiful, blonde woman who carries the sword Excalibur. She manifests as a Saber-class Servant.

Artoria is a reserved and noble Heroic Spirit who was summoned by Chaldea as an organization, so she currently lacks a Master. Instead, whenever a truly dangerous mission comes up, Artoria tags along to increase the chance of success with her incredible prowess with Excalibur and her ability to heal herself with the holy scabbard, Avalon.

Artoria possesses the ability to unleash Excalibur as a Noble Phantasm, creating a massive blast of magical energy capable of destroying a fortress or landscape with ease.