General

Night Lords have the lowest defense of all thieves, I think. The only thing that helps their survivability is Adrenaline's pot efficiency and their slightly extra health. However, Night Lords can easily avoid some attacks by Flash Jumping while attacking, or just jump attacking. Also, Showdown makes it easier to avoid damage from bosses. So overall, if you can utilize Night Lords' versatile mobility, you can end up taking somewhat less damage.
Dual Blades still have low defense, but slightly more survivability because of life drain, their extra avoid, and their dashing skills that keep them from being damaged. Also, damage can be reduced a little for Dual Blades.
Shadowers have lots of defense and survivability, especially with Shield Mastery, Mystic Potions, and Meso Guard. They don't have as many mobility skills as Dual Blades, but they're hard to kill.

Evasion Rate skills are also a multiplier, so DB's have an easier time hitting that 90% cap like @iDivideZer0 mentioned (and were godmode essentially pre-Unleashed with no cap in place except for % HP attacks that ignore Evasion Rate and Dodge Rate).

NL's still have the lowest total Evasion Rate out of all Thieves (including Xenon and post-revamp NW) even after factoring in 9999 Avoid because they have no Evasion Rate multiplier skills to increase their Avoid further. Since they also lack Damage Reduction skills (DB would have 20% from summoning Mirrored Target), their survivability is that of a glass cannon per se.

There's a difference between dodge rate and avoid. NL has 45% dodge rate and DB has 70% avoid.

From my understanding,
Dodge rate is a flat rate, so for NL you have a 45% chance to dodge an attack from ANY monster regardless of the monster's acc.
DB's Avoid is factored in after you calculate the %avoid you have between you and a monster. Avoid is also capped at 90%, which isn't hard to achieve on a DB.

@TripleBladez has a better explanation of this down in the comments [url=http://www.basilmarket.com/forum/2810952]http://www.basilmarket.com/forum/2810952[/url]

[quote=janny1993]Mirrored Target gives you 25% avoid, not 10%.... unless he haven't max it yet.
And with Shadow Meld, that's another 30%, Side Step is another 15%, giving you a total of 70% avoid rate.

That is what keeping dual blade alive most of the time as they rarely get hit. I rarely notice life drain helps at all in critical situation.

The reason why he spent so much potion in the evo world is because of the quantity of the monsters, there are more monsters in evo world so the chances of getting hit is that much higher, draining his hp even faster, which is why his hp decreases so fast that life drain won't even help at all.

Life Drain only works well when he don't get hit as frequently as in evo world (or on bosses that always hit regardless avoidability)[/quote]

Monster Park Extreme not evo world. The 10% avoid difference I was referring to was the difference between shifter and shadow meld + mt. I forgot about side step. 70% avoid rate is ridiculous, and that explains why I never have to use potions

If you're getting 2hkod your issue isn't avoid, it's max HP. Pretty much what vTwlit said, look for ways to get more passive HP.

Lol I laughed when you mentioned your NL dies in two hits to everything. Yes, Night Lord's HP is fairly low, you might want to try and get some set effects, %HP link skills, and character card sets can add quite a bit to your HP as well. At level 208 I have about 26k HP with all those things, and I avoid a great amount of hits. I only ever die to moves that 1 hit you.

Based on you saying MPE I'll assume your nightlord is under 140 and therefor doesn't have shadow shifter maxed.

DB's have lie drain that has a 10% chance per hit to heal you which is HUGE (My drk has simular and near never uses hp pots). DB's also have 25% more dodge (70% instead of 45%(NL)

Once you max shadow shifter you'll effectively half your hp pot usage. Nightlord survivability is actually pretty high but if you're getting 2 shotted by MPE mobs I'd suggest getting a few char cards to boost hp. (3 70+/100+ cards together is like 2000 more hp each set)

[quote=Anthoy84]Life Drain is what's keeping you alive, not the extra avoid from Mirrored Target.

It procs very frequently when you're killing multiple monsters.[/quote]

Mirrored Target gives you 25% avoid, not 10%.... unless he haven't max it yet.
And with Shadow Meld, that's another 30%, Side Step is another 15%, giving you a total of 70% avoid rate.

That is what keeping dual blade alive most of the time as they rarely get hit. I rarely notice life drain helps at all in critical situation.

The reason why he spent so much potion in the evo world is because of the quantity of the monsters, there are more monsters in evo world so the chances of getting hit is that much higher, draining his hp even faster, which is why his hp decreases so fast that life drain won't even help at all.

Life Drain only works well when he don't get hit as frequently as in evo world (or on bosses that always hit regardless avoidability)

Life Drain is what's keeping you alive, not the extra avoid from Mirrored Target.

It procs very frequently when you're killing multiple monsters.