Hephaestus is the god of fire and blacksmiths in Greek Mythology. He's the creator of Achille's shield and the woman Pandora.

A difficult birth

To avenge from Zeus who gave birth alone to Athena, Hera decided to do the same, but the child she gave birth to, Hephaestus, was born deformed, ashamed, she cast him out of Olympus. He was then raise by the nymph Thetis.

Once he reached adulthood, he went to Olympus, seeking for revenge. He crafted a gold throne for Hera and when she sat on it, she was tied by many invisible ropes.

Then, all the deities try to convince Hephaestus to free his mother, but he denied all their requests, even in exchange for becoming an Olympian. Finally, Hera got freed thanks to Dionysus, who made Hephaestus drunk.

Hephaestus and Aphrodite 

Hephaestus crafted a belt which made whoever wore it irresistible. Aphrodite, scared that someone could become more attractive than her, decided to marry Hephaestus in order to take possession of the belt. 

Thus, the ugliest god and the prettiest goddess are now married together.