oh, "Vampy" is sortof the official JP name, that was kept by a good majority of the cygames fanbase, yet the official translation of her name "Vania" originated in the initial EN localization of Rage of Bahamut, since then, it's stuck from the original localization source.
how else would we get memes like this?
to writ, both "Vampy" and "Vania" are correct, just my personal bias goes with the official translation.
P.S:
I possess volumes 1-3 of Arisa Duelverse, can't read it worth a damn, but I might be able to help.