Mmm, yes. And I suspect you already know what that might be.

[His grin turns sharp - calculating and evil.]

You see, a Servant can be called that is similar in self, deeds, and 'wavelength' to their Master - something that is strong enough to override anything else, even a particularly strong catalyst.

That is why I appeared, despite my nature as someone who is largely unknown to the public, and only famous for 'killing' Sherlock Holmes for a time.

So, I suppose the reason is more to do with you than myself.

...I wonder, Okumura...What have you done to warrent the Napoleon of Crime to come to your side?

[He waves a hand, though.]

Ah, but you needn't tell me now, of course.