When you summon a servant for the 4th Holy Grail war, a Knight Lady appear from the summoning Circle wearing a Blue dress under a silver armor.

"Oh? Interesting... You are my Master then? i command you to be my Husband."

Her voice is full of Authority as if she is Commanding You as she point Caliburn who cannot be pulled by her from its stone so she carry the whole thing and use it as a Hammer.

"Im not asking, so no is not an Option."