Jurisdictions

Before a bauta stone, Skuld's elven mother gives Hrolf the sword Skofnung.

(Bauta stones commemorate the dead or the absent living. For the second purpose, they are appropriate to Poul Anderson's Starfarers:

When we see a name on an ancient monument, we know that the named person is dead but, when Kith traders see the names Jean Kilbirnie and Timothy Cleland on Monument Stone in the Kith village on the planet Harbor in the system of Tau Ceti, they know that Jean and Tim, unaged, are on a ten thousand year round trip, still alive but as inaccessible as if they were dead.
- copied from here.)

Svipdag, swearing brotherhood, calls to witness:

"...Frey of the earth, Njord of the sea, and Thor of the heavens." (Hrolf Kraki's Saga, p. 131)

So far, we have seen references to Aegir of the Sea but Njord is more appropriate since he is a god. This reminds us of other divine triads -

Olympian
Jupiter, sky
Neptune, sea
Pluto, underworld

Ysan
Taranis, sky
Belisama, earth
Lir, sea