The weakest Master.
The default name is Kishinami Hakuno.
An exceedingly normal 17 year old student.
We designed him/her with the idea that he/she would be about the third most attractive in their class.
…Is what we intended anyway. A lot of players pointed out that with the female protagonist being as cute as she is, her class would have to be pretty high level in terms of student appearances.
Just like the protagonist of an RPG, Hakuno doesn’t speak throughout the game, has no personality, and maintains a neutral stance.
Hakuno usually expresses his/her ideas through simple monologue, but when the story comes to a branching point, the options presented are his/her own words.
He/she is a wizard of average ability.
Hakuno possesses high-quality magic circuits, however up until the point of their awakening he/she had not practised using them at all, so they are mostly wasted.
Although Hakuno ends up participating in the Holy Grail War, even after the preliminaries are finished he/she is unable to remember his/her memories from before coming to the moon. Hakuno has no idea who he/she is, or why he/she is participating in the Holy Grail War, and he/she continues to fight in order to find the answers to these questions.
Although Hakuno is affected by amnesia, he/she still retains basic knowledge about the world, so there is no problem managing his/her daily life.
After entering the main storyline of the game Hakuno is still in a completely blank state where he doesn’t even know the difference between right and left, but it seems like his/her basic education was at a level that was rather odd high.
Hakuno sports some amazing detective skills and inference ability in the sections where he/she needs to guess the true name of each heroic spirit by only going on the fragments he/she has gathered from the game matrix. Perhaps Hakuno was a history maniac in the past.
While not significant in any way, there is a passage in the game where Hakuno has his own opinion about Francisco Xavier.

Also, Hakuno holds onto hope that was born from within some tiny part of him/herself.
Hakuno is extremely average in every way, and is like a sheep who grew up in a pen where there is no danger or need to fight for one’s survival.
Thought the one waiting in SE.RA.PH’s throne.
No matter how you look at it, this Holy Grail War belongs to Leo.
Leo is an outstandingly talented individual who is well suited to win the Grail, and I1 understands that Leo is essentially the king of the real world. When facing Leo, even if they are unable to come to terms, their meeting is surely something significant.
Per my prediction, the young King Leo will become the strongest individual yet to win the Grail.
—and that’s precisely why.
It’s precisely because Leo is the strongest, that Hakuno can improve his/her ability through his/her prodigious body and manage to defeat his/her strongest opponent, that he2 was able to catch sight of salvation.
It’s precisely because there is conflict that humans improve.
The King of Conflict will take up SE.RA.PH’s throne, and wait for the arrival of the crystallization of his ideals.
No matter how many times Hakuno was defeated, his/her knees did not buckle, and he waits for the moment where Hakuno surpasses the limits of his burned-out husk of a body.

Translator’s Notes
  1. ^ First person POV thoughts from “the one waiting in SE.RA.PH’s throne” (Twice H. Pieceman).
  2. ^ Switching back to third person POV. The second half of this entry is talking about the thoughts/motivations of of Twice H. Pieceman.
Fate/EXTRA Material: Encyclopedia of Fate/EXTRA