Kotone

Rin's classmate, who was kidnapped by Gilles and Ryuunosuke. A young girl with a murky fate.
In the first draft, I unthinkingly named her “Satsuki” and ended up getting punished by the original author. I had totally forgotten that Satsuki was Sacchin's real name—or rather, I had forgotten that Sacchin even had a real name at all! To all the Yumizuka Satsuki fans around the world, I humbly beg your forgiveness.
Kinoko: “Urobuchi… please, a little consideration…”
Gen: “But… without a 'Satsuki,' suffering isn't moe!”
Well, anyway, a conversation like that may or may not have actually happened.

Fate/Zero material: Fate/Zero Encylopedia