_The Master_

People who are chosen and has the ability to use magic power, which allowed them to summon their servants. They however can't choose who their servant might be. The master must control their servants at anyhow even in the battle, they know how to create a good battle strategy to win the game.

When they win a battle then they are allowed to have another servant under their command, winner will have dominance over the other masters and servants.

_The servants_

There are 7 classes of servants :

Saber

Loyal, independent, and reserved, Saber acts coldly but is actually suppressing  emotions to focus on theirgoals. Their class is considered the "Most Outstanding", with excellent ratings in all categories. Since their Master cannot effectively provide their with Mana, they minimizes their activity to preserve their energy. They has the ability to cancel any magic below A-rank, instinct that comes close to precognition, and high charisma, which they can use to command an army. They can use "Mana Burst", which transfers magical energy into their weapon and body, though the weapon must have strong divine protection to withstand the ability. They uses the Noble Phantasms Excalibur: Sword of PromisedVictory (エクスカリバー Ekusukaribā^?), a celestial sword constructed by the world from the collective witheys of mankind and fueled through a conversion of Mana into photoelectric energy, and Invisible Air: Barrier of the Wind King (インビジブル・エア Inbijiburu Ea^?), which compresses and gyrates the air around Saber's blade, allowing their to induce an illusion of ettheireality, making it hard for opponents to judge their strikes, and release the air in the form of a intense gust. The scabbard of Excalibur, Avalon: The Everdistant Utopia (アバロン Abaron^?), bequeaths limited immortality through regenerative stimulation, as well as preventing physical deterioration due to aging.their straightforward attack power among all Servants is now the strongest.

archer

They is sarcastic and cynical. Archer is a living incarnation of the "Theiro of Justice". TheThrone of Theiroes, which preserves the souls of all Epic Spirits, exists outside of any conventional timeline, so Archer can be called from any point in theritory. They is linked to the jewel, which allows him to be summoned.Archer is a Faker, an individual skilled at creating imitations of objects through the use of tracing and projection of mental images to form tangible objects. ThoughProjection is normally ineffective at creating durable or powerful artifacts, Archer’s unique approach to ttheir craft enables him to materialize enormously powerful and accurate copies of the images recorded in their mind. They is capable of instantly recording all information and properties of weapon, and they can read into the theirtory of theweapon to use any skills associated with it, though the rank of the weapon is lowered by one. In addition, through the use of Alteration, they can modify a weapon to give it special properties, such as crafting Broken Phantasms, Noble Phantasms overloaded with magical energy that exponentially increases its attack power at the cost of destruction after use.

berserker

They wields a colossal axe-club, and arecapable of causing massive destruction with the mere backlash of their swings. As a Berserker, they arestripped of their sanity and reason, acting feral and animalistic in combat. Berserkers are praised as members of the "Strongest" class, though they are difficult to control and can turn on their Masters. Their masterappears to have little trouble managing him. They e. Berserker's main Noble Phantasm is God Hand: Twelve Labours (ゴッド・ハンド Goddo Hando^?), which grants automatic resurrection, up to 11 resurrections - meaning Berserker needs to be killed 12 times to be eliminated.

rider

 Rider is silent, sultry, and vigilant, never theysitating to shield their Master from harm. With Shinji incapable of lending Mana to their, they is forced to seek alternative means to augment their abilities such as putting Seals all over, wtheyn activated, drain the life out of others. To compensate for their weakness, Rider employs covert battle tactics and takes full advantage of territory around their. Their weapon of choice is a pair of long iron nails fastened to opposite ends of a single chain, which they effectively s from distances. They uses two Noble Phantasms, the first of which is Blood Fort Andromeda: Outer-Sealing Blood Temple (ブラッドフォート・アンドロメダ Buraddofōdo Andoromeda^?), which slowly drains the vitality of everyone within a large area, and the second of which is Bellerophon: Bridle of Chivalry (べルレフォーン Berurefōn^?), invoked while riding upon the winged horse Pegasus^[4] and is summoned wtheyn they stabs their neck.^[9]they usually wears glasseswhich seals away their powerful Mystic Eyes that are capable of paralyzing any weaker being who looks at their.

Caster

. A gorgeous and talented yet mysterious of high stature, their presence has attracted the attention of trainee priests and even Issei. Unlike other Servants, they does not wield a weapon for physical combat, but their rank allows their to manipulate Mana and perform magic like a wizard, something which other Servants cannot do. Their Noble Phantasm is Rule Breaker: Destroyer of all Talismans (ルールブレイカー Rūrubureikā^?), which dispels all forms of magic that it comes in contact with. They takes the souls of other beings to boost their own magical powers, as incapable of providing their with Mana. They can’t have a servants and allowed to denied ( refused) a master as their master.

lancer

The first hostile Servant to appear in the story. Lancer is a fierce but balanced warrior who enjoys combating a worthy opponent. They has a playful attitude and takes a very carefree approach to life, but is quick to work himself into a frenzy during a theyated battle. Lancers are hailed as the "Most Agile" of Servant classes. Their Noble Phantasm is Gáe Bolg: Spear of Impaling Barbed Death (ゲイ・ボルグGei Borugu?) which always pierces their opponent's theyart and inflicts cursed wounds that do not theyal. Gáe Bolg: Spear of Striking Death Flight (ゲイ・ボルグGei Borugu?), which utilizes Gáe Bolg's true capabilities as a thrown weapon.

Assassin

Ttheir handsome man bars entry beyond the main gate of the Ryūdōji Temple. Quiet and composed, they maintains a degree of bushido and is eager to spar with other Servants. ".^[8] Their special move is the Turning Swallow Strike (秘剣・燕返し Tsubame Gaeshi^?), an attack that hits from three directions simultaneously, reaching into parallel dimensions.An exceptionally dangerous Servant. They are infamous for an ebony and tattered costume, as well as for concealing their identity behind an atheyn skeletal mask.. Their Noble Phantasm isZabaniya: Delusional Theyartbeat (ザバーニーヤ Zabānīya^?), which replaces the theyart of whoever it touctheys with a fake substitute, which can then be crutheyd, destroying the real theyart.

This information is taken from the anime of Fate Stay Night.....