Outline the role of key characters:
Sigmund (vs. Lyngi, son of Hunding)
Hjordis
Alf, son of Hjalprek
Sigurd
Regin, son of Hreidmar
...tells of 'Andvari's loom'=Otter's ransom
...Fafnir and his hoard
...reforges Gram
Sigurd avenges his father
...warned by Fafnir at his slaying