User blog comment:SayuriDarling/Magnus Chase and the Gods of Asgard Official Discussion/@comment-25044056-20150731010624/@comment-5471249-20150731144310

Frigga - a more pleasant and less irascible and vengeful version of Hera, hopefully.

Sif - nothing like the Marvel Comics version! She's associated with earth and fertility in the myths, so she'll probably be a less fussy and overprotective version of Demeter.