Vamp: Stories

Eugene was a vampire who chose to hide—twelve long years spent starving in the mountains, fearing discovery. When he was finally found, a so-called holy knight toyed with his life, using him as bait to gain fame as a Vampire Slayer. His head was severed, his existence erased… or so it should have been. But fate had other plans. Eugene awakens back in the past, five days before everything begins.

Our Mc's drunk dad married a rich widow [who is his girlfriend's mom], and instantly his girlfriend became his stepsister. Things got twisted when he found out the widow and her daughter are vampires and are searching for a rare bloodline to increase their power. And consequently, that is happening to be our MC.