I mean, I'm not opposed to revising the concept
But I know for a fact that tapping Valaya for it won't fulfill the same role.
Nah, I want Gromril + Preservation + ??? To evoke the earth and Meteor colliding, and the impact destroying and purifying
what lies between the two as they meet through said conflagration
Not exclusively gromril, but the land too being cleansed through fire.
Yeah on the Crown though.
Im not nearly as well versed in Warhammer as other folks. If you've got a better way To make it work in mind, I'll shamelessly leap at the opportunity.
So to evoke that idea of destroying and purifying what is between the two in a conflagration though would basically take two set pieces because you can't do it all with the Armor. If we try to make a hammer out of his armor it will flop pretty hard, because armor runes aren't really designed for it.
So put the Rune of Valaya on the armor, because Valaya is where the purification and anti-chaos and some serious protective aspects of the Dwarven Pantheon live, see the Daemonward combo on Snorri's cloak and the Inner Gates and her general role, and it can represent the ground/anvil you mentioned last page due to its sturdiness. Valaya is also about the
Hearth and Home and this entire thing with the prosperity of the king's impacts revealing purified wealth is very in theme with benefiting his hearth and hold and home, as evoked by this idea you raised:
The aftermath of the Meteors Fall brings forth threefold bounties to the Hold: Strength to Protect, Wealth for the Forge, and Boundless Opportunity, waiting to be grasped by its King.
(Which yes I know is for the Crown but it still applies because purification and benefiting Hearth and Home is what Valaya does and the armor can easily tie into this idea you're talking about)
So to complete the other half, the hammer, we can use a Talisman to more strongly evoke the idea of his passage through the metaphorical sky or army and then striking the target, purifying it with the presence of Valaya through the Rune of Valaya on his armor and the flames conjured by Trollslayer and the Cloak and the Talisman.
Thus he has a focus of his impact (Trollslayer), the great explosion and unstoppable force surrounding him at the moment of impact (Pyrestrike), a Adamant body whose presence is inimical to impurity and from whom comes great wealth (Armor), and his speedy burning passage from the void to the ground (Talisman). That hits most of the notes you want I think, except for the Kingship thing, and I'm pretty sure we don't know the lesser form of the Rune of Kingship. We'd have to see about giving him a second talisman in the Crown, which should be possible, and it means we can stack more Runes of Valaya or Grungni (since Grungni is the King of Kings) and the Rune of Kingship once we learn it. Grungni might also be a good choice because then Otrek would have an item with one of each of the Main Three Ancestor's runes. We could also do Kingship + Grungni + Valaya because part of Grungni's domain is Wealth and Mineral Rewards like gold.
Now if V3 of my plan where I switch things around so Otrek has the Rune of Valaya and Gloin has the Rune of Sanctuary doesn't end up winning I don't think that's too big of a deal because the Rune of Sanctuary we know is harmonious with the Rune of Valaya. Because of the Daemonward combo, and because Valaya is the goddess of Home and home is a sanctuary, and because the Rune of Sanctuary is about enhancing natural anti-magic. That anti-magic stands against Chaos and Magic and provides something of a inimical to impurity effect, and it will probably combo with master rune of Gromril + Preservation.
So in sum, you need two pieces to do what you want and the best way to do that is use a Talisman and the Armor we're making.
