The Jotnar
The Jotnar — the "giants" — are the wild powers the empire never conquered: an older, unedited strain of the same cosmic stock as the Aesir, embodying the raw forces of nature the gods spent eons trying to tame. They hail from Jotunheim and the primordial fire-realm of Muspelheim, and they are bound up with the Aesir by war, marriage, hostage, and grudge.
Half the court of Asgard carries jotunn blood and would rather not discuss it. Loki discusses nothing else.
TODO: the clans, the primordial powers, and the role of the Jotnar in Ragnarök.