Holy Grail War but the Protagonist Is Shinji

In a parallel world of a certain moon, the vigorous Fifth Holy Grail War ended, and everything seemed to have come to a seemingly successful conclusion. However, due to some small differences, it caused huge changes in the world like the flapping of a butterfly's wings. Let's not talk about the specific changes, but our second master really became the so-called protagonist. Shinji: "The Holy Grail War is over, and my stage has just begun!" This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.