Fighter from Cityplace starts with an iron sword, it gets broken in battle, and the blade is reforged with a better steel. The new weight makes it unwieldy, so adjustments are made to the hilt to rebalance the weight, which also gets some steel involved. As the blade sees more combat and gets repaired with quality steel, it eventually becomes a steel blade with a high level of design refinement, as well as having absorbed the magical essences of many mighty creatures.
Seeing the perfectly crafted blade, a novice crafter from Cityplace asks to borrow the sword to learn from it, in exchange for a good titanium sword that serves as a serviceable replacement. The fighter accepts, and starts to hone the new titanium sword through expensive repairs and epic combat to slowly include bits of mithril, allowing the sword to move slowly towards being composed of only mithril.
A letter summons the fighter back to the crafter in Cityplace. They’ve learned all they can from the sword, even enhancing it up to mithril, and getting it primed for magical gems and runes to be added to the hilt and blade respectively. The crafter asks if they may have the titanium sword back to learn from, offering to cover the cost of repairs and enchantments to the sword that used to be made of iron. The fighter accepts, and trades the powerful but mundane titanium sword for an extremely powerful and highly-enhanced mithril sword.
There are now two swords that this fighter and crafter have made a part of history through their continued actions. After ascending to the ranks of the highest crafters in the land, that crafter can now take raw adamant ore and turn it into the finest custom swords around. Meanwhile, having slain some of the greatest of beasts and acquiring a blade of otherworldly materials, they no longer require the services of their crafting ally. The sword that was once made of iron is now a legendary item, held as the symbol of improvement and perseverance that guide’s the fighter’s own guild. The crafter uses their first mithril sword, reforged and honed just as the iron sword was, as a symbol of learning and dedication which guides their crafting union.
Years later, after they’d both taken their leave to travel the world, tragedy strikes Cityplace. An invasiion of multiple hostile forces leads to the ruin of Cityplace. The leaders of these groups now squabble over the spoils, as one Orc captain tries to get their hands on both the legendary swords of Cityplace to infuse with magics and powers that were not available to the crafter and fighter. Upon hearing the news of the demise of Cityplace, the fighter and crafter join forces to build an army to reclaim the stolen weapons, which are now even more powerful than when they were last used.