Isaac’s reference is the Forgemasters from the Castlevania fictional universe Castlevania is an American adult animated dark fantasy action streaming television series on Netflix. Based on the Japanese video game series of the same name by Konami, the first two seasons adapt the 1989 entry Castlevania III: Dracula's Curse and follow Trevor Belmont, Alucard, and Sypha Belnades as they defend the nation of Wallachia from Dracula and his minions. Isaac (アイザック Aizakku) is a major character in the Castlevania animated series. Initially, appearing as an antagonist, serving as one of Dracula's two human generals in his army (the other being Hector), he later plays a more protagonistic role. A Devil Forgemaster (悪魔精錬士 Akuma Sērenshi) is a human trained in the dark arts and, akin to their namesake, bears the ability to create and forge demonic and wicked creatures. Mainly known simply as "Forgemasters" instead of manifesting Innocent Devils from pure darkness, the main way both Hector and Isaac are able to utilize their magic is by performing rituals with special tools, either to bring people and animals back from the dead or to call demonic spirits from Hell into intact corpses, transmogrifying the bodies and turning them into creatures of the night in order to enlist them in Dracula's army. Their methods, however, seem fundamentally different: Isaac is only seen using his dagger and magic to forcibly transform a person, or body, directly into a night creature. Isaac is said to be pulling the souls of former humans turned demons out of the underworld and into fresh new bodies.. Another unique aspect of the powers displayed by each Devil Forgemaster is their color. Isaac's and Hector's magic manifested with a red and blue glow, respectively, allowing anyone to discern which night creature/undead was forged by whom.