I haven't played a warrior in so long. I was thinking of a role for Arial Warrior, Sword & Daggers specs, Villager Berserker. Now I do not know few things.
--- What legacies?
*Weaknesses
Lag: This can be fixed with Landslide or potentially STSF, though with arials new 22 int I think it would be somewhat slow to charge. There is also potential in space between hearbeats to lag opponents you catch trying to run down a road or juggle weapons, but I don't think this is as strong as the other two.
{Landslide, STSF}
Burst Damage or Unblockable Damage: There are a few approaches for this like Soul of the Mountain for more HP, Gates if you think you can gear for AC, Flow of Shadow to evade more attacks all together, Cry of Thunder to heal and gain haste if you didn't want to bloodthirst, and Whispers to heal quickly (though this can be negated). I would suggest Fluid, but it negates extra chances for riposte/concealed.
{Soul, Gates, Flow, Cry, Whispers}
*Strengths
Defense: You will defend incredibly well with sword, but you could potentially increase that with Dance as well as help your concealed strikes with dagger. I would not advise Ward because you could get extra parries with daggers that could have instead been concealed. You could choose Fist to always hold your weapons, but bloodthirst negates the strength loss later on so as long as you don' t mind using it liberally you really don't need it.
{Dance}
Unblockable Damage: You will have an insane amount of unblockable damage with concealed and riposte, so why not make it hurt even more with Chilling. If you often face numbers, another tactic with arial and sword is to go into the room with all of your opponents and wingsweep. If there are three or more of them you will riposte better with the Seven Winds edge, so you will begin tearing them up while not getting hit much because of the anti-gank code. You could combine this tactic with Mercy to become meaner every time one of them flees.
{Chilling, Mercy}
Flurry: Contrary to what Scrimbul said, Flurry is extremely good with speed flurry and can be made even better by using Cry before flurrying.
{Cry}

I would say read through what fits your playstyle best and choose one from weakness and one from strength. If you are still clueless after this, I would likely advise taking landslide and soul for great all around ability.
--- What edges would fit best?
For every dex sword spec regardless of second spec the edge order would begin with
*Parry Anything
*Evasive
*Seven Winds of the Hamsah Mu'tazz
As you are dagger, I would probably take *Reckoning of the Mongoose next.
After this, it begins to get down to your fighting style. If you will try to avoid numbers even in raid situations, you will get huge mileage out of *Ehren Soul and potentially *Ehren Lord.
Any more you will likely just want to choose edges to help balance out the strengths of your opponents.
--- What should I gear for?
How willing are you to call bloodthirst at the first sign of stat-loss? If so, gear for hp, saves, and damage. If not, gear for stats, saves, damage and hp. That is at least what I would guess, but haven't played this in village before.


Can someone please explain STSF? How does it work and do I have to logged on for hours before I get benefits?
I will let others better suited explain this.

If I plan to play Duergar Warrior, what should I go with?
--- What legacies?
--- What edges would fit best?
--- What should I gear for?

In truth, the main difference between duergar and arial is that duergar has more hp and maybe slightly worse defense with swords if for sure worse defense with daggers. I would say Dance and Gates jumps up on the list while Soul potentially jumps down, but much of the other advice remains the same.