Fate/strange Fake - Vol. 2 Ch. 10

[MangaDex]

 

[Serpent-niisama]

So basically she's Sajou Ayaka from Fate/Prototype with hair dyed gold, though in afterword of light novel volume with this events author says she isn't. Interesting.

 

[Human_the_2nd]

Ah yes, Nero + Proto Arthur = Best boy