Holy Grail War: Three Kingdoms

It is said that a Holy Grail appeared in ancient times, and anyone who gets it can realize a wish. Later, people started fighting to snatch it... Why did the Holy Grail appear, and why could only one person get it? Is all this a gift from God, or a joke and temptation from the devil? When the Holy Grail came to the ancient East, old books fell into even older spiritual liquid... I don't know since when, the back of the boy's hand started to feel itchy, and the classmates around him also became strange... Until one day, a comet streaked across the sky, and the struggle for hegemony a hundred years ago will be re-enacted in the modern era in another form!