FATE/RWBY Child Mage Male Reader X RWBY Servant

When (y/n) Emiya decides to join his older brother and sister in fighting in this years Holy Grail War, he learns that summoning a servant of his own is much harder than his siblings made it look. However at the very same time as (y/n) begins the ritual to summon his servant a strange phenomenon occurs causing (y/n)'s...