Hephaestus

Hephaestus is the god of metalwork and fire. His wife is Aphrodite, even though she is disloyal to him, going out on dates with Ares. His most famous demigod child is Charles Beckendorf, who is said to be able to make anything with metal.

Appearance
Hephaestus is a huge lump of man with a leg in a steel brace,a misshapen head and a wild brown beard.

Hephaestus appears in The Battle of The Labyrinth tells Annabeth and Percy that Hera (not Zeus) threw him down from Mount Olympus, adding spitefully that Hera is only interested in having a "perfect family".

Hephaestus does not appear in The Titan's Curse, but one of the settings is his junkyard, where Bianca di Angelo died.