Fate/ Grand Crypter

What if the 48th Master of Chaldea is missing? A story without a protagonist is like a house of cards, it will simply collapse under its own weight. Such a story is doomed, from the very start. How do you save such tale? This is the conundrum that Leo, the man sent to replace the hero, finds himself in. Fortunately, Chaldea is full of capable individuals, able to resolve such struggles themselves. With Team A, the Crypters of Fate/ Grand Order's Act 2, one can save the story, even without it's original hero.

This is the story of an ordinary man's attempt to save the Crypters, and his journey with them to save the world.

Disclaimer: I don't own the original work.