[Suzerain of Sheol]

It's an axe that looks like a giant stuffed paw. When you kill an enemy with it, there's a 10% chance that you steal a duplicate of one of their equips.

Then, there's Character World, which lets you go inside your party members' souls to power them up in various ways. While in there, you can run into clones of your characters... exact clones, down to their equipment.

So, if you just equip your guy with that perfected level 300 Testament with 8 300-level Statisticians in it... and you kill the clone with the Puppy Paw Stick... you get the idea.

It's very tedious, very luck based, and the shop glitch is much, much more abusable.