... How many dead people has Lisa fucked (coming from me, it's only curiosity, not judgment)? Heck, in Makai Tensho, Amakusa's childhood friend had necro-sex with him to give birth to his new body, like with Casca, giving birth to the demon baby, which grew into Griffith's new body. Also, given that it's a lie, anyway, not going for broke and saying the Fuhrer himself, Frau Brenner?
Edit: Reading through Marie route, one of the lines says that Rusalka believe that Mercurius is "5 times younger" than herself. In other words, she places his age at the same as most of the Round Table. In other words, she only knows him as "Karl Krafft". Therefore, I have to ask, how many of the Round Table actually know Mercurius as his other names? Those that predate the Third Reich, and yes, the irony of one of those identities for those of the Third Reich.