I was able to (briefly) talk to Asakawa Yuu-san today (among many other things, 
she supplied the voice bank for Megurine Luka and was also the voice actress 
for Rider from Fate Stay Night. Unfortunately we weren't allowed to record the 
talk event, but she complimented me on my Japanese and answered my question. 
I asked her about the experience of voicing Rider 
and what it was like participating in Fate Stay Night. She said that she 
first voiced the character in the anime and got to know her character from her 
design - busty, tough-looking, cool, and so on. Yuu-san observed that Rider 
did not live very long, but that something else Fate-related was in the works. 
Much later on during the talk she yelled Bellerephon (the power word Rider 
uses to activate her Noble Phantasm).