Caster (Alice)

The Servant from the third round.
I am you, and you are I.
For you who have even forgotten your own name,
I will mimic your exact appearance.
My name is Nursery Rhyme.
Tommy Thumbs’s cute picture book.
The very first version of Mother Goose.
A romantic flight that continues through the night,
For the you and I who are dreaming.
Ahh, but alas the elevator descends.
The end of the dream has come along.
The end of Alice has come along.
This is a story, so of course it has an end.
The lonely you and the sad me.
Let us grant our final wish.

Nursery Rhyme is not a true heroic spirit; she is the manifestation of a real picture book.
The picture book genre, which is deeply loved in England, has stimulated the dreams of many a child. Nursery Rhyme is essentially a heroic spirit born from children; by children and for children.
(Nursery Rhyme is the book which eventually became the foundation for Lewis Caroll’s famous works. One of his great works, Alice in Wonderland, is actually a nursery rhyme he improvised while entertaining his nieces.)
The Servant Nursery Rhyme is actually a pseudo-Servant dreamt up by her Master. She is a Reality Marble that embodies a reflection of her Master’s feelings.
This servant managed to save her tragic Master, and at the same time also saving her mirror-like self who is nobody. …even though it is something that is meaningless and fragile like sweets.
Also the prose poetry included above is the same as in the game’s “Matrix Details: 1” section.
Before the final battle with Alice there is the “Let’s guess their true name!” event, and after that the poem is displayed. In the poem, the line “Let us grant our final wish.” is a reference to a desire of Alice’s that is not from when she was alive, but rather from after her death when she became a ghost.

Fate/EXTRA Material: Encyclopedia of Fate/EXTRA