Rubeus Hagrid time. It's unknown if Fang is still alive when Harry's children come to Hogwarts. Fluffy is a giant three-headed dog provided by Hagrid to guard the trapdoor leading to the underground chamber where the Philosopher's Stone was hidden until the end of "Philosopher's Stone". The only known way to get past Fluffy is to lull him to sleep by playing music. Fluffy is based on Cerberus, the three-headed dog from Greek mythology that guards the gates to the underworld. As with Fluffy, Cerberus was lulled to sleep with music by Orpheus. In "Philosopher’s Stone", Harry, Ron, Hermione and Neville accidentally
Greek underworld Greek underworld In mythology, the Greek underworld is an otherworld where souls go after death. The original Greek idea of afterlife is that, at the moment of death, the soul is separated from the corpse, taking on the shape of the former person, and is transported to the entrance of the underworld. The underworld itself—sometimes known as Hades, after its patron god—is described as being either at the outer bounds of the ocean or beneath the depths or ends of the earth. It is considered the dark counterpart to the brightness of Mount Olympus with the kingdom of the dead