Laura was the "daughter" of Carmilla, who took her from her true parents and turned her into a vampire many centuries ago. She first meets and challenges Gabriel to a game of supernatural chess, in exchange for passage into Carmilla's castle. After the defeat of Satan, Laura calls to a distraught Gabriel and enlists his aid against the Forgotten One, a mighty Demon that Gabriel released when he slew the Lords of Shadow, during which time, they develop a strong and deep bond which culminated in Laura giving her blood, power and life to Gabriel to transform him into a vampire, attain the strength to defeat the Forgotten One, and subsequently become the Prince of Darkness.

Castlevania
Castlevania: Hymn of Blood is an interpretation of a possible backstory for Simon Belmont, the protagonist of the Castlevania video games. It should come as a relief to old-school gamers that the serialized story seems to focus more on references and lore from the three NES games, rather than anything from the more recent (and terrible) games.