Alright, so let me pitch an idea I intend to use for the Tohr:

The enclaves of Tohr Skivlieg's elves are warm, humid rainforests hidden away in volcanically active crags and defiles out in the realm's hinterlands. They're alien environments, sustained by both rich soil and ancient magics beyond the understanding of the current residents. The elves are 'uncivilized' in comparison to their cousins in that they're a bit closer to their fickle, fey roots and not exactly the more common angelic Tolkienesque fair folk. They're pale, black-eyed alien folk.

Now, despite their differences, the springelves and the Tohr have come to terms with one another. They sealed a pact long ago, in the wake of some primordial struggle, perhaps with the bigger, nastier giants or some dragons or something, and part of this pact was an exchange of goods.

Now here's the rub. I want to introduce a magical material, one that's inspired, no, wait, wholesale ripped from Pathfinder and D&D, that's a product of the elfish hot springs. The theory was that the trees of the region, warped by mysterious enchantments, suck up minerals from the geothermally heated waters in the soil. The trees that die can be chopped down and the metal that collected in their trunks can be gathered, treated, and smelted into 'living steel'. Living steel would be a vaguely green, glimmering metal that can grow back into the shape it was forged into. You know, essentially regenerative steel for weapons and the like. Weapons forged of the steel would be family heirlooms, many of them hundreds of years old, all bereft of nicks and scratches.

Really, it'd be more fluff than some sort of min-max gameplay mechanic considering how slowly that stuff would probably reform. No clutch, critical reshaping of a sword in a pivotal duel or anything.