Blacksmith Momet:
If you need dual weapons, Momet's your blacksmith! Anything is possible, except for A-grade weapons! I wonder if anyone's better than me. Maybe Mammon's own legendary blacksmith?
You just need to bring me your sword, a Stone of Purity, and a small fee.
Dual weapons are formed by combining a Normal weapon with another Normal weapon, a Basic weapon with another Basic weapon, and a Rare weapon with a Normal weapon. Rare weapons are actually B-grade or higher.
And you can't combine weapons that have options on them so don't even bother bringing those.
Oh, if you combine enchanted weapons, those effects will disappear so don't get mad at me about that!