When you categorize optimal sword spec usage you take strength and dexterity into factor. Of all races, duergar hold the highest altitude for both stats and I believe them to be the best race in MY OPINION . I love fire giants equally for their resist, but duergars can yield some nice dam roll with optimal rager stat use (-svs spell for spellbane, dam for deathblow, and maybe -AC for gates + resist to stack redux)
So you want to be a sword master RBW at hero and be feared?
Gates will help you get there. Stack rager resist and you're sitting with 1200+ hp that doesn't shave off easily. Duergar vuln will hurt, but you will be a mean machine with (geared properly) easily 70~100 dam roll deathblowing and riposting people's faces off.
Second spec and legacy are up to you but I've always liked the idea of staff/spear and maybe Cry of thunder for non-bloodthirst haste and healing.
Dern armor will put you where you need to be for gates dam redux and increase your saves vs. spell with spellbane. Dwarf/duergar are rager champs.
If you want good forged weapons, there is always a dwarf in the village these days you can ask so don't worry about losing out on the added hit/dam