“The guardian of the vessel – my duty is to manage and transport the ‘vessel’ prepared for the Holy Grail’s descent. Actually, that’s not completely accurate.

During the previous Heaven’s Feel, not only did Grandfather Acht lose his Servant, the precious ‘vessel’ of the Grail was also broken during to the war. In the Third Heaven’s Feel, since the ‘vessel’ was damaged before the victor was decided, the war was meaningless. That’s when Grandfather began to reflect and decided to cover the ‘vessel’ this time inside a humanoid shape that has a consciousness and can self-manage.”

Her nonchalant voice was as if she was leisurely recounting things that have nothing to do with her. It was probably because she’s seen through everything that she had decided to speak out everything about her body.

“And that is – me. The ‘vessel’ itself was granted the instinct to live. In order to dodge all sorts of dangers by itself, Grandfather made the ‘vessel’ into ‘Irisviel’.”

- Fate/Zero: Act 12, Part 2