Nice to meet you Scorpius... Son of Malfoy? Do humans do the same kind of last names as us? We use the name of a parent as the last name, like "so and so son of so and so."
Oh as for me, I don't have a last name as I don't have parents. Technically its just "The Necromancer". So all in all my name's Necrosis the Necromancer.