Reading : Master and His Ruler Servant

A group of people including the masters and servants of the fifth holy grail war were gathered in a white room to read the life of Emiya Shirou from another world. What would happen if Emiya Shirou summoned a Ruler Class Servant instead of Saber? What if the Servant he summons is not an ordinary Servant, but a Shinobi Emperor and a Samurai? NB : OC, OOC