This entry only concerns the 2 manga that are present in the artbook "Fate/stay night 15 Years of TYPE-MOON", called "Fate/15th Camp" and "Curtain Call" respectively. 
Fate/15th Camp is a collaborative work of 14 artists and one writer.

Based on the third route of Fate/stay night.

In a certain regional city of Japan called Fuyuki City, a Holy Grail is said to appear once every few decades, capable of granting any wish to its owner. Seven magicians form contracts with seven heroic spirits and engage in the conflict known as the Holy Grail War to obtain the Holy Grail. Rin Tohsaka, who was raised in a family of magicians, also aims to participate in the Holy Grail War, following her father Tokiomi Tohsaka's legacy. However, as she attempts to summon the greatest heroic spirit Saber, things take an unexpected turn...

The story takes place in an ordinary Japanese town, Fuyuki City. Hidden from society, there has been a deadly war going on in this town. Seven sorcerers known as "Masters" summon a powerful familiar called "Servants" and they all fight each other till the last one. The last one is said to attain the Holy Grail which will grant them a wish. Only a few knows when this War started and what the Holy Grail is, but the war was about to begin again this year. 
The main character is Emiya Shirou, who lost his parents in a fire and was adopted by a man who called himself a sorcerer. Admiring his step father, he has been training himself to be a sorcerer. However, he had no talent and he could barely use one type of sorcery. His step father has already passed away, and today he's a sorcerer without any skills or knowledge. He is involved in the War of the Holy Grail when he accidentally summons Saber, who is said to be the strongest servant of all... 
Note: The chapter count includes 62 regular chapters and 5 bonus chapters.

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