So my brother is a Pokemon nut and I got am idea off a video he sent me. And no its not a Pokemon mob. Please don't make a Pokemon mod because half my players will beg me to add it 10 times a day. I know its going to happen but anyways back to the subject.

So the basic idea is this. There are some sort of rare or legendary creatures. You have a base weapon crafted and you use the souls of those creatures to increase the power of the weapon. I imagine this would take making a new weapon and adding crafting recipies where the next upgrade recipie is the previous version plus the soul of one of the legendary creatures.
This is probably far beyond my capabilities depending on how easy it is to create weapons and crafting recipes once the editor is released bit guess we'll see. I might even make it a quest so you have to go back to an npc and pay them to do the upgrade and wait x days per level it becomes.

This was the video that inspired the idea.
Watch "Top Amazing Pokemon as Weapons Fan Art Compilation Requests #1" on YouTube put these in the game as legendary weapons lol