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• The anime mainly follows the Fate Route
• Caster's Antagonist Role later in the anime is adapted from Unlimited Blade Works. (In Fate, she appears but is shortly killed. Her goal to prematurely summon the Grail was one of the main plots of Unlimited Blade Works).
• Sakura's attacks on Rin in their battle during Caster's Arc is adapted from Heaven's Feel.
• The Unlimited Blade Works Movie adapts the Route of the same name in the Visual Novel. However, it is more faithful to the adaptation than the original anime (I say faithful in a loose sense - you can't be faithful to a few hour long game in a movie).
• The Unlimited Blade Works Anime series by Ufotable adapts the Route of the same name in the Visual Novel. is a more faithful then the movie because it doesn't try to compress everything into one movie. it also expands on the fates of a couple of characters who simply disappeared in the route

1. Fate/Zero
2. Fate/Stay Night (anime, if you really have to)
3. Unlimited Blade Works (I'd watch Ufotable's series over Studio Deen's movie)

• The anime mainly follows the Fate Route
• Caster's Antagonist Role later in the anime is adapted from Unlimited Blade Works. (In Fate, she appears but is shortly killed. Her goal to prematurely summon the Grail was one of the main plots of Unlimited Blade Works).
• Sakura's attacks on Rin in their battle during Caster's Arc is adapted from Heaven's Feel.
• The Unlimited Blade Works Movie adapts the Route of the same name in the Visual Novel. However, it is more faithful to the adaptation than the original anime (I say faithful in a loose sense - you can't be faithful to a few hour long game in a movie).
• The Unlimited Blade Works Anime series by Ufotable adapts the Route of the same name in the Visual Novel. is a more faithful then the movie because it doesn't try to compress everything into one movie. it also expands on the fates of a couple of characters who simply disappeared inadapts the Route of the same name the route
• The Fate/Stay Night: Heaven's Feel movie trilogy is suspected to adapt the Route of the same name (however currently only the first movie has been realsed)

1. Fate/Zero
2. Fate/Stay Night (anime, if you really have to)
3. Unlimited Blade Works (I'd watch Ufotable's series over Studio Deen's movie)
4. Fate/Stay Night: Heaven's Feel movie trilogy

While you say you don't intend to read the Visual Novel, you would miss out a lot. The Visual Novel isn't constricted to screening times, as such you can get quite detailed explanations of Nasuverse terminology such as True Magic, Magecraft, The Throne of Heroes, and how it's used with the Holy Grail. A lot of these are explained in the Unlimited Blade Works and Heaven's Feel Route, The latter has yet to been release (thouygh here's an Aniplex trailer).

While you say you don't intend to read the Visual Novel, you would miss out a lot. The Visual Novel isn't constricted to screening times, as such you can get quite detailed explanations of Nasuverse terminology such as True Magic, Magecraft, The Throne of Heroes, and how it's used with the Holy Grail. A lot of these are explained in the Unlimited Blade Works and Heaven's Feel Route, The latter has has only just been released partially as a movie with more films to be released.

• The anime mainly follows the Fate Route
• Caster's Antagonist Role later in the anime is adapted from Unlimited Blade Works. (In Fate, she appears but is shortly killed. Her goal to prematurely summon the Grail was one of the main plots of Unlimited Blade Works).
• Sakura's attacks on Rin in their battle during Caster's Arc is adapted from Heaven's Feel.
• The Unlimited Blade Works Movie adapts the Route of the same name in the Visual Novel. However, it is more faithful to the adaptation than the original anime (I say faithful in a loose sense - you can't be faithful to a few hour long game in a movie).

In terms of which Visual Novel, Fate/Stay Night Realta Nua PC is your best bet as Realta Nua uses the same updated engine as what Fate/Hollow Ataraxia uses. Realta Nua PC is for all ages and in Japanese. There is an English Patch for it and it does add an option to view both the original H Scenes from the original Visual Novel and their Realta Nua Replacements (Shiro and Saber's Bed Scene, Rin's Contract with Shiro, Rider stealing Prana from Shiro).

• Fate/Extra (PSP Game) - This is set outside Fate/Stay Night. in the 1970's a certain event has drained Prana from the world. There are cameo's from Fate/Stay Night like Kotomine, Taiga, Rin's Lancer and Sakura, but their roles are different and not related to the original. Also, the Rin in this title, while looking like Rin from Fate/Stay Night, is not the same Rin but a descendant of Fate/Stay Night's Rin by at least 2 generations (implied to be either mother or grandmother).

• Fate/Extra CCC (PSP Game) - A split from Fate/Extra like Heaven's Feel is to Fate/Stay Night. Sakura has a much larger role which also adds Gilgamesh into the mix. However, he's not so much as an ass as he is in Fate/Stay Night (though proudly showing off his naked body in front of Elizabeth as a weapon does show he's still got that ego).

• Fate/Apocrypha (Novel) - If you've watched Fate/Zero or Played the Visual Novel then you know of the 3rd Holy Grail War. Fate/Apocrypha splits from the 3rd war where the Grail was stolen from Fuyuki. In this story, there are 2 teams of Servants and a new class, Ruler, which acts as mediator over the war. Also Mordred is summoned as Saber, keeping an established tradition in Fate series: the main Saber is related to Fate/Stay Night's Saber.

• The anime mainly follows the Fate Route
• Caster's Antagonist Role later in the anime is adapted from Unlimited Blade Works. (In Fate, she appears but is shortly killed. Her goal to prematurely summon the Grail was one of the main plots of Unlimited Blade Works).
• Sakura's attacks on Rin in their battle during Caster's Arc is adapted from Heaven's Feel.
• The Unlimited Blade Works Movie adapts the Route of the same name in the Visual Novel. However, it is more faithful to the adaptation than the original anime (I say faithful in a loose sense - you can't be faithful to a few hour long game in a movie).
• The Unlimited Blade Works Anime series by Ufotable adapts the Route of the same name in the Visual Novel. is a more faithful then the movie because it doesn't try to compress everything into one movie. it also expands on the fates of a couple of characters who simply disappeared in the route

In terms of which Visual Novel, Fate/Stay Night Realta Nua PC is your best bet as Realta Nua uses the same updated engine as what Fate/Hollow Ataraxia uses. Realta Nua PC is for all ages and in Japanese. There is an English Patch for it and it does add an option to view both the original H Scenes from the original Visual Novel and their Realta Nua Replacements (Shiro and Saber's Bed Scene, Rin's Contract with Shiro, Rider stealing Prana from Shiro).

• Fate/Extra (PSP Game) - This is set outside Fate/Stay Night. in the 1970's a certain event has drained Prana from the world. There are cameo's from Fate/Stay Night like Kotomine, Taiga, Rin's Lancer and Sakura, but their roles are different and not related to the original. Also, the Rin in this title, while looking like Rin from Fate/Stay Night, is not the same Rin but a descendant of Fate/Stay Night's Rin by at least 2 generations (implied to be either mother or grandmother).

• Fate/Extra CCC (PSP Game) - A split from Fate/Extra like Heaven's Feel is to Fate/Stay Night. Sakura has a much larger role which also adds Gilgamesh into the mix. However, he's not so much as an ass as he is in Fate/Stay Night (though proudly showing off his naked body in front of Elizabeth as a weapon does show he's still got that ego).

• Fate/Apocrypha (Novel) - If you've watched Fate/Zero or Played the Visual Novel then you know of the 3rd Holy Grail War. Fate/Apocrypha splits from the 3rd war where the Grail was stolen from Fuyuki. In this story, there are 2 teams of Servants and a new class, Ruler, which acts as mediator over the war. Also Mordred is summoned as Saber, keeping an established tradition in Fate series: the main Saber is related to Fate/Stay Night's Saber.

• Fate/Prototype - This was what Fate/Stay Night could have been feature a Male King Arthur with a Female Master. the Holy Grail War also different with a different purpose.

• Lord El-Melloi II Case Files - a side series following Lord El-Melloi II, AKA Waver Velvet from Fate/Zero, and Gray, a Descendant of Arturia's Bloodline, as they investigate mysteries in the thaumaturgy world generaly set around Clock Tower in London.

• Fate/Labyrinth - set in the Seventh Labyrinth of Caubac Alcatraz (a Dead Apostle Ancestor) where someone had installed and activated one of the Subcategory Holy Grails in Caubac' labyrinth. Manaka Sajyou from Fate/Prototype appears but is now an existence connected to Akasha possesses the body of Norma who summons Arturia. this series is also one of the cases Lord El-Melloi II and Gray investigate