Why Gunslinger Sub?
Gunslinger sub allows you to easily obtain more than 30% speed with their speed buff without sacrificing too many points into speed. You also get two traps to add to your already powerful DoTs, and a decoy skill that is very helpful in higher level dungeons. The bombardment mastery for -10% target's defense is also very useful.
Distributing ATK/DEF Points
DMG - All your extra ATK points will go into DMG. Points spent into DMG will also increase the damage of your DoTs
CRIT - Spend enough points into crit until you have at least 50-60% unbuffed CRIT
SPD - Spend enough points into speed until you have at least 30% with Mental Focus. DoTs will tick every .9 sec at 10% speed and every .8 secs at 30% speed
HP - All the extra points after DEF will go into HP
DEF - Spend enough points into DEF until you have at least 16k-17k unbuffed which is enough for otherworlds and dragons
EVA - Any extra points left after HP will go into EVA
Frost Trap/Dark Flare Trap>Slash Cut>(repeat until you need to recast the Slash Cut debuff)Cross Slash>Snowflower>Deadly Wink
If you are not jump casting your skills, leave Snowflower out of your rotation. When you do jump cast Snowflower there is no need to jump cast Deadly Wink since the animation for Snowflower is very short and you can cast Deadly Wink before landing. You should jump cast all your skills, because it will allow you to sneak in auto-attacks in between casting your skills increasing your dps. You should also remember to back stab as much as you can unless you pull aggro, then allow your party members to back stab instead.
General Skills: Crackling Slash or Precision Bombardment
Use Crackling Slash for the extra DoT, but Precision Bombardment for -10% defense would be best overall.
Attack Spec: Zeal is the best dps attack mastery.
Advanced Skills: Exploding Wolf Trap for the extra ten levels added to Dark Flare Trap. Use From the Shadows if there is someone in your party with a higher level Dark Flare Trap.
Defense Spec: Courage or Extreme Speed. Use Extreme Speed when doing b2b in otherworlds and courage for everything else.
Tactical Spec: Break Defense or Organized Sabotage.
Special Skills: The Best Defense.
This is the current envoy path at level 75.
You can choose not to take the ultimate skill since it's only use is to save your life, and not oftenly use. Remember to jump cast your ultimate too.
If you don't want the ultimate you can take fleet footed or determination.
A lot of people seem to think Caustic Venom isn't a great envoy and prefer to take Cross Slash envoys. What most people don't know about Caustic Venom is that it ticks for a total of 15 times within 3 seconds, then there's a burst of damage after. It is recommended to have Caustic Venom over the two Cross Slash envoys(the 16% is additive to the skill's 130% base multiplier). The +2 meter AoE is too small to be that effective. If you want AoE, you can take the two Deadly Wink envoys and spam Deadly Wink while Purple Lightning is up. With the envoys, Purple Lightning, and enough speed you should be able to cast Deadly Wink as soon as the GCD is down.
Bel-Chandra: +25% normal attack speed, 5% flat crit, crit buff, 20% crit dmg buff
Yarnaros: +25% normal attack speed, 8% dmg
Endora: 5% flat crit, 8% dmg, target takes 30% more crit dmg(needs Endora's Black Cat)
Eligos: +25% normal attack speed, 8% dmg
Zaahir: +25% normal attack speed, 5% flat crit
Bel-Chandra and Yarnaros would be best. If you don't feel like jump casting all your skills or if you have the Lion's Roar set go for Endora.
Serif: -50% crit dmg taken, 10% HP
Sigrun: -50% crit dmg taken, 5% def
Aelius: 5% movement speed, 5% eva, -30% crit dmg taken buff, cleanse/dispel
Kotonoha: 5% movement speed, 5% eva, 10% lifesteal, -10% target's dmg, speed buff
Tsubaki: -50% crit dmg taken, 5% def, lifesteal, -10% target's dmg, speed buff
Vermillion: -50% crit dmg taken, -5% dmg taken, 8% lifesteal
Serena: -25% chance to suffer critical hits, 10% HP
What Gears to Choose
Lvl 1-49: Choose any gear you wish to wear it doesn't really matter.
Lvl50-59: For armor you can either choose to use top requiem and bottom aria or the full aria set.
You'll want a weapon with either holy or ice element. Ice element is best if you are focused on single target. Holy element to increase your AoE damage. You should also stack as much boss damage as you possibly can.
Demonic Blades would be your best choice to deal the most damage. It provides 10% boss damage, a bonus damage proc, and a weapon core of your choice.
Zaahir blades is a good alternative to the Demonic Blades. It has 2% lifesteal, 8% HP, 50% bonus damage to flame targets, and an 8% detailed damage proc.
These blades offer a nice crit buff and 5% HP.
This build is currently using the Nazrudin blades. It gives a nice 8% HP bonus and +25% damage to one of your most used skills Cross Slash. It is also always ice element which is good for Snowflower.
The Soulless and Sorrow are great if you don't want to go through the trouble of crafting many Demonic Blades for a high %. It has a bonus damage proc and adds 10 seconds to the duration of purple lightning. The 10 seconds does not affect the -20% damage taken buff from purple lightning. Also you don't even need to main these blades to make use of the effect you can just switch to them when you are going to cast purple lightning then switch back.
These are the only guns you should use above level 60, because of the 10% boss damage. You could also use blue guns with 12% boss damage instead. You craft the guns with either a deadly, destroyer, or nocturnal core.
Armors (top set)
If you can't at least +15 your devourer I suggest you use this set. Titan tops provides -20% damage taken from bosses and a good amount of HP and defense.
This is the best top set for dealing damage to bosses which should be your main focus as a duelist. Don't be fooled by stats given by revelations and the 65 top sets. The 15% boss damage allows Devourer to outdps all other top sets except Ambusher.
Armors (bottom set)
To start off at level 60 you should use this set for the 15% boss damage.
If you can fortify your armor to +15 or higher you should use this set. If you can't afford to fortify this set, then you may be too squishy since this set gives no HP at all. This set allows sacrifice less points into crit because of the flat 11% crit and you get a nice 70% bonus damage proc.
If you want to build for a more tanky duelist then go for this build. It allows you to cap crit damage very easily and the proc Enthusiasm, +50% normal attack speed, is nice if you don't have very high speed which shouldn't be a problem with the gunslinger buff and Flokja set.
This the best and cheapest set to start off with if you can't afford to get the Flokja set yet. It adds damage, HP, and speed.
This is the best overall set out there for any DPS class. It provides a lot speed and a 70% bonus damage proc.
These trophies are a must when dealing damage. These trophies both give a nice bonus damage proc. You can switch out the orange one for a different trophy when you're not fighting bosses.
If you jump cast to utilize auto attacks and want some extra lifesteal, then use this trophy. The lifesteal effect from this trophy only affects auto attacks, not skills.
After you're done gearing up, you can still improve your duelist by getting elemental trophies. These trophies will help increase your damage when dealing with a specific type of element. Just switch out a green or orange malodnak for one of the elemental trophies corresponding with the element type you're facing.
You should have 2% dmg on all your stones. The second stat can be crit dmg, or -% dmg taken.
To decide whether you should use thunderous or zephyr stones. If you can't afford high fortified gear, use thunderous stones for the extra 16% HP. If you can afford to lose the extra HP you should definitely go for the extra damage from zephyr stones and defense from The Best Defense.
Hat: 2% HP, 10% boss damage
Face: 2% DMG/-2% DMG taken, Cross Slash Mastery
Clothing: 2% DMG/-2% DMG taken, 25% Boss CRIT DMG
Ornament: 2%DMG/2% HP, Extreme Speed Mastery/Mental Focus Mastery
Weapon: 2% DMG, Dark Flare Trap Mastery
The Finished Product
The Devourer tops are currently +17 and +16 and it's not upgraded to +20 since this build is waiting for 70 gears to come out. Iit is missing out on 4% HP and 8% Crit DMG though.
The Nazrudin blades are 137%, Duke's Duelers were crafted with a destroyer core, and the trophies and Devourer were crafted with bestial cores. This build is currently using thunderous stones for weapons.
This is the duelist with no buffs on.
This is the duelist fully self-buffed with two-star Eligos
This is the duelist fully self-buffed with three-star Yarnaros
Otherworld Parties Solo
Otherworld Hells Solo
Landing of the Sky Dragon King Solo
Siege of the Aqua-Dragon Queen Solo
Credits: Special thanks to Phil Nguyen for making this very informative guide on Duelist.