I think Seidr is the best because it's a cause of overcoming, accepting and saving yourself all in one story.
I would argue Reginn and Fjorm had similar developments. Fjorm accepted to die to take a gamble to save Laegjarn showing she's not senlessly hating Muspell folks for what they did. Reginn had her whole moment against Fafnir the issue is that without her sword and Eitri being terrible writing in goblin form due to Otr not much came out of it.
I also stitched this one together, I like the stare.