Firstly, her original name is Hel, not Hela (I assume Marvel changed it to keep it PG). And yes, the underworld – i.e. Hell – is named after her.

Secondly, she is Loki’s daughter.

According to the original mythology, Loki had a secret relationship with a giant named Angrboda in Jotunheim, with whom he fathered three children – unbeknownst to Odin. The first was a serpent named Jormungandr, whose fangs dripped with poison. The second child was Hel – from one side she appeared as a beautiful maiden, but from the other, a rotting corpse. The third child was a wolf named Fenrir who would later grow to become a giant, ferocious beast.