I don't mean to get off on a rant here.....
I am a die-hard vampire fan and the earliest mention of a half human/half vampire is in Russian fokelore, they were called Dampyres or Dunpiels,which is where the writers of Vampire Hunter D got the name. Legend says they were vampire hunters for hire, and possesed special powers that aided them in this. (hmmm yet again, VHD, which by the way, I am a huge fan of.) Most so called "dampyers" were con men who would take advatage of a village in suffering, blaming whatever was plauging the poor folks on a vampire. He'd then tell them he'd kill the vampire, for a modest fee of course. Once he was payed he'd march out to the graveyard and go into some skit that varried but always had him point our the "invisable vampire" which he would do battle with, putting on a grand show for he poor dumb saps who were watching. He'd then slay the monster and let out a trilling whistle annoucing victory, as per the legend. Of course he'd hitail it out of town before people realized nothing got better. But THIS is where the half breed hunter story comes from, not Blade, not VHD, it's a legend, so if you're gonna bust this movie as a "ripoff" you can go after Funmation or whoever because Dragonball is based on "Seiyuki" or "The Journey West" a Chinese legend about the Monkey King Son Goku who helped a monk tavel to India to get the sacred sutras of Buddhism.