"Blood dolls live a short period on a certain amount of vampire blood (which starts the so-called engine). The better versions, Blood Doll ++, can live longer and can feed itself when neccessary, and it doesn't matter whose or what blood... Well, the rest is up to your imagination, hahaha." (Source: Blood Doll ++ [LINEART VERSION]
I haven't said it yet, because I didn't think it would have been interesting to do so. I wanted to dedicate something to Blood Huntress, but didn't know what. After brain storming I concluded I should draw fanart of Vampire Knight. Some time after, I had this daydream about living dolls and vampires. O__o"