Blacksmith Hilda:
So you met with Vulcan, did you? Did he give you an earful of his madness? Well, he's mad about flame, but the rewards he offers are real. Defeat the monsters in the Gods' Forge, collect the flames you find, and go to him; he will give you an S-grade weapon recipe if you bring him 1000 flames.
If you gather even more flames, you might see about meeting Vulcan's younger brother Rooney. He's as mad as his brother, and he's engaged in the same quest. Bring him 1200 flames and he will give you an S-grade weapon recipe.. Rooney wanders from here to there, so he's not easy to find...but it might be worth your while to deal with him.