Vesper (ヴェスパ) is a character in .hack//Epitaph of Twilight. He is mentioned in the Epitaph of Twilight.
Vesper, a black cat, is Saya's familiar.
When Lara Hoerwick finds herself in the world of the Epitaph, Vesper is the first being she meets. Throughout the story, he is her source for all sorts of information about the world, and helps her pass as Saya, until he dies to defeat Cubia.