I'd like to take an Lead sword + 10 lead Bars and upgrade it to lvl 2 then as I keeping upgrading it reach a lvl that you would need new materials instead only ore bars and the aparence or atack effects would change, the npc who change stats now would give new stats with GEMS that you could craft or found but if you doesn't have any gem he could randomly give a gem to your sword making it have elemental damage or crit changes
But the whole upgrades about size of your weapon and stuffs like that could be done in an special crafting item like a big forge that you could put your sword and some materials and make it bigger or small or different
Since your sword reach lvl up it would have different names like "Master Lead Sword" and since that it would need new items to upgrade and me it better and better,
Swords like Arkhalis and other swords that have beautifull effects and forms that you don't use could be usefull for upgrade and make it stronger
But the whole upgrades about size of your weapon and stuffs like that could be done in an special crafting item like a big forge that you could put your sword and some materials and make it bigger or small or different
Since your sword reach lvl up it would have different names like "Master Lead Sword" and since that it would need new items to upgrade and me it better and better,
Swords like Arkhalis and other swords that have beautifull effects and forms that you don't use could be usefull for upgrade and make it stronger