@Lelygax
Supposedly, it's not outright stated Kokoro and Julius are related. I base this on an edit someone made to the CV wiki, but I can't verify it myself. My theory: Kokoro is 16 in 2011, meaning she was born around 1995. Because of this someone wrongly included the unnamed brother is Julius. This makes no sense because Otomedius clearly doesn't take place in the same world as Castlevania.
Yet she is a Belmont, thats why I said that my reasoning isnt to be taken SO seriously, we are talking about a parody.
Also I've read it in Gradius wiki and in Wikipedia that Julius is her older brother, not only in CV Wiki.
http://gradius.wikia.com/wiki/Kokoro_BelmontA picture would be good, thanks Pfil.