Neo's Dual Blade Guide

[Neothisis]

Guide updated:06/29/2011 - Added Chaos build, added more DPS tables.
Guide is updated with a Chaos build. Still tentative for the time being, I need to know how point saving will work in Chaos, if it's the same as Big Bang or different. I'll also be leaving the Big Bang build guide up for a while, until more versions update to it. The build includes using the Cash Shop Mastery books, if you're not using them, just subtract the extra +1 SPs for your count. All in all, it'll only be 6 extra SP for those that did use them.

Chaos:

Spoiler!

1st Job:

Spoiler!

10:1 Double Stab (1)
11:3 Double Stab (4)
12:3 Double Stab (7)
13:3 Double Stab (10)
14:Save (3)
15:Save (6)
16:Save (9)
17:Save (12)
18:Save (15)
19:Save (18)
Double Stab is your initial basic attack skill. You need 10 of it to get Triple Stab, and the rest of the 2nd job skills are much more important than anything else in 1st job at the moment, so save up for those once you get 10 Double Stab.

2nd Job:

Spoiler!

20:10 Triple Stab (10), 5 Katara Mastery (5), 6 Katara Booster (6)
21:3 Katara Mastery (8)
22:3 Katara Mastery (11)
23:3 Katara Mastery (14)
24:3 Katara Mastery (17)
25:3 Katara Mastery (20)
26:3 Katara Booster (9)
27:3 Katara Booster (12)
28:3 Katara Booster (15)
29:3 Katara Booster (18)
30:2 Katara Booster (20), 1 Disorder (1)
Triple Stab is going to be your main single target, or even dual target, skill up until 3rd job. Mastery increases your minimum damage, very useful, be sure to get it. You can leave Mastery at 19 instead of 20, there’s no damage difference, I honestly prefer 20 over 19, and as such, my guide reflects that.

2nd+ Job:

Spoiler!

30:1 Slash Storm (1)
31:3 Self-Haste (3)
32:3 Self-Haste (6)
33:3 Self-Haste (9)
34:3 Self-Haste (12)
35:3 Self-Haste (15)
36:3 Self-Haste (18)
37:2 Self-Haste (20), 1 Slash Storm (2)
38:3 Slash Storm (5)
39:3+1 Slash Storm (9)
40:3 Slash Storm (12)
41:3 Slash Storm (15)
42:3 Slash Storm (18)
43:2 Slash Storm (20), 1 Shadow Resistance (1)
44:3 Shadow Resistance (4)
45:3 Shadow Resistance (7)
46:3 Shadow Resistance (10)
47:3 Shadow Resistance (13)
48:3 Shadow Resistance (16)
49:3 Shadow Resistance (19)
50:1 Shadow Resistance (20), 2 Disorder (3)
51:3 Dark Sight (3)
52:3 Dark Sight (6)
53:3 Dark Sight (9)
54:1 Dark Sight (10), 2 Nimble Body (2)
55:3 Nimble Body (5)
Alright, well, Self-Haste first since Triple Stab is a pretty strong skill in itself, and mobility is essential as a Thief. Get 1 Slash Storm in the beginning to get your first real mobbing skill. After Self Haste, max Slash Storm, it’s useful for damage, distance, and mobbing and upgrades into Bloody Storm later on. Next up is Shadow Resistance. You probably won’t see its effects very much at this point, 10% is a minimal gain with the HP a level 4x Dual Blade will have. The status resistance will come more in handy once you start bossing at higher levels. Finish off 2nd+ job with Dark Sight to get you set for Advanced Dark Sight later on. At this point, you still have a level to go, and the game doesn’t let you save points from 2nd+ to 3rd, so you can put points in whatever you want. I chose Nimble Body for the Avoidability bonus. The reason why Fatal Blow isn’t here is because it’s not worth it honestly. It’s a very slow skill, only single target, and while it IS stronger than Triple Stab, the 30 SP put into is not worth it because Upper Stab is stronger (in terms of damage per second) by level 4 and it even mobs.

3rd Job:

Spoiler!

56:1 Flash Jump (1), 1 Tornado Spin (1), 1 Upper Stab (1)
57:3 Upper Stab (4)
58:1 Upper Stab (5), 2 Flash Jump (3)
59:3 Flash Jump (6)
60:3 Flash Jump (9)
61:3 Flash Jump (12)
62:3 Flash Jump (15)
63:Save (3)
64:Save (6)
65:Save (9)
66:Save (12)
67:Save (15)
68:Save (18)
69:Save (21)
70:Save (24)
Alright, well, one of each at 56 to mess around with, get Upper Stab to level 5 so that it’s better than Fatal Blow as far as DPS goes, then max Flash Jump for movement. After that, save your points until 3rd+ because Flashbang isn’t too useful yet, and Tornado Spin is much more useful when chained with Flying Assaulter.

3rd+ Job:

Spoiler!

70:10+1 Flying Assaulter (11), 1 Vital Steal (1), 10 Bloody Storm (10), 1 Chains of Hell (1), 1 Advanced Dark Sight (1), 1 Owl Spirit (1), 1 Mirror Image (1)
71:3 Tornado Spin (4)
72:3+1 Tornado Spin (8)
73:3 Tornado Spin (11)
74:3 Tornado Spin (14)
75:3 Tornado Spin (17)
76:3 Tornado Spin (20)
77:3 Mirror Image (4)
78:3 Mirror Image (7)
79:3 Mirror Image (10)
80:3+1 Mirror Image (14)
81:3 Mirror Image (17)
82:3 Mirror Image (20)
83:3 Mirror Image (23)
84:3 Mirror Image (26)
85:3 Mirror Image (29)
86:1 Mirror Image (30), 2 Flying Assaulter (13)
87:3 Flying Assaulter (16)
88:3 Flying Assaulter (19)
89:1 Flying Assaulter (20), 2 Upper Stab (7)
90:3 Upper Stab (10)
91:3 Upper Stab (13)
92:3 Upper Stab (16)
93:3 Upper Stab (19)
94:1 Upper Stab (20), 2 Advanced Dark Sight (3)
95:3 Advanced Dark Sight (6)
96:3 Advanced Dark Sight (9)
97:1 Advanced Dark Sight (10), 2 Vital Steal (3)
98:3 Vital Steal (6)
99:3 Vital Steal (9)
100:1 Vital Steal (10), 2 Owl Spirit (3)
101:3 Owl Spirit (6)
102:3 Owl Spirit (9)
103:3 Owl Spirit (12)
104:3 Owl Spirit (15)
105:3 Owl Spirit (18)
106:2 Owl Spirit (20), 1 Chains of Hell (2)
107:3 Chains of Hell (5)
108:3 Chains of Hell (8)
109:3 Chains of Hell (11)
110:3 Chains of Hell (14)
111:3 Chains of Hell (17)
112:3 Chains of Hell (20)
113:3 Flashbang (3)
114:2 Flashbang (5), 1 Nimble Body (6)
115:3 Nimble Body (9)
116:3 Nimble Body (12)
117:3 Nimble Body (15)
118:3 Nimble Body (18)
119:2 Nimble Body (20), 1 Disorder (4)
120:3 Disorder (7)
Here’s the advantage of saving up 25 SP. Get Flying Assaulter to 11 so that you can chain max Bloody Storm and Tornado Spin with it. Currently, you can’t do either, so max Bloody Storm and put 1 point in everything else. Now start maxing Tornado Spin so you can chain that as well. These 3 skills basically define your new way of training for the rest of your Dual Blade career. Next up is Mirror Image. Very useful, all your attacks get double the number of hits, with the Mirrored ones being 70% as strong at max. Now max Flying Assaulter to get all the damage from that as you can since you’ll be using it a lot. Then max Upper Stab as it’ll be your finishing move once you execute a Flying Assaulter combo. Next up is Advanced Dark Sight. Allows you to attack in Dark Sight, which is essential for being able to use Chains of Hell multiple times in a row without coming out of Dark Sight, as well as the damage bonus for all attacks when you’re in Dark Sight. Vital Steal is very useful with all the multi-hit skills and invincibility frames Dual Blades have. Owl Spirit, if it activates, is a significant boost in damage while it lasts, so you’ll want to use it often. Sadly, its use is limited at bosses, but there are still chances to use it. Chains of Hell is really useful in boss fights due to its invincibility frames, as well as being an effective single target skill. You can also cancel the actual attack of Chains after just pulling a monster closer to you to make for some effective mobbing strategies. Flash Bang does work on bosses, which makes it extremely useful. -85% Accuracy at max level and your character’s Avoid stat pretty much leaves you invincible for the 20 seconds it's in effect. Once again, you’re left with no other skills to max, so it’s back to the basic. Nimble Body and Disorder are really the only options, unless you really want points in Lucky Seven or Fatal Blow.

4th Job:

Spoiler!

120:1 Blade Fury (1), 1 Phantom Blow, 1 Final Cut (1)
121:1 Mirrored Target (1), 1 Venom (1), 1 Sharpness (1)
122:3 Sharpness (4)
123:3 Sharpness (7)
124:3 Sharpness (10)
These are your first few basic skills. Mirrored Target's passive effects are great and are definitely worth the 1 point into it. Sharpness is your passive Critical skill. Important. Get it.
Training Build:

Spoiler!

125:3 Final Cut (4)
126:3 Final Cut (7)
127:3 Final Cut (10)
128:3 Final Cut (13)
129:3 Final Cut (16)
130:3 Final Cut (19)
131:3 Final Cut (22)
132:3 Final Cut (25)
133:3 Final Cut (28)
134:2 Final Cut (30), 1 Blade Fury (2)
135:3 Blade Fury (5)
136:3 Blade Fury (8)
137:3+1 Blade Fury (12)
138:3 Blade Fury (15)
139:3 Blade Fury (18)
140:3 Blade Fury (21)
141:3 Blade Fury (24)
142:3 Blade Fury (27)
143:3 Blade Fury (30)
144:3 Venom (3)
145:3 Venom (6)
146:3 Venom (9)
147:3 Venom (12)
148:3 Venom (15)
149:3 Venom (18)
150:3 Venom (21)
151:3 Venom (24)
152:3 Venom (27)
153:3 Venom (30)
Final Cut increases the damage of most of your skills while it’s active, thereby increasing your overall damage output. Blade Fury is your new mobbing skill, and although its range is kind of small, the damage is high and definitely useful in many situations. Venom is a useful damage over time skill, and with all the hits you’re unleashing, it’ll stack up really quickly.

Bossing Build:

Spoiler!

125:3 Phantom Blow (4)
126:3 Phantom Blow (7)
127:3 Phantom Blow (10)
128:3 Phantom Blow (13)
129:3 Phantom Blow (16)
130:3 Phantom Blow (19)
131:3 Phantom Blow (22)
132:3 Phantom Blow (25)
133:3 Phantom Blow (28)
134:2 Phantom Blow (30), 1 Hero's Will (1)
135:3 Thorns (4)
136:3 Thorns (7)
137:3 Thorns (10)
138:3+1 Thorns (14)
139:3 Thorns (17)
140:3 Thorns (20)
141:3 Thorns (23)
142:3 Thorns (26)
143:3 Thorns (29)
144:1 Thorns (30), 2 Final Cut (3)
145:3 Final Cut (6)
146:3 Final Cut (9)
147:3 Final Cut (12)
148:3 Final Cut (15)
149:3 Final Cut (18)
150:3 Final Cut (21)
151:3 Final Cut (24)
152:3 Final Cut (27)
153:3 Final Cut (30)
154:3 Venom (4)
155:3 Venom (7)
156:3 Venom (10)
157:3 Venom (13)
158:3 Venom (16)
159:3 Venom (19)
160:3 Venom (22)
161:3 Venom (25)
162:3 Venom (28)
163:2 Venom (30), 1
Phantom Blow is your final single target skill. Fast and strong, this is what you’ll be using pretty much the entire boss. You should be one the main DPSers, especially since you won’t be doing much mobbing without Blade Fury. Get Hero's Will here to get out of situations in which you're Seduced or something else. Thorns gives a stance effect as well as 30 attack, so that’ll be really useful as well, to directly and indirectly increase your damage output. Final Cut is a significant damage boost while it’s on, as well as a big amount of damage in itself with 2000%. Finally, Venom works on bosses, so that’s last up to bring up your total damage output.

My Planned Build:

Spoiler!

120:1 Phantom Blow (1), 1 Blade Fury (1), 1 Mirrored Target (1)
121:1 Venom (1), 1 Final Cut (1), 1 Sharpness (1)
122:3 Sharpness (4)
123:3 Sharpness (7)
124:3 Sharpness (10)
125:3 Final Cut (4)
126:3 Final Cut (7)
127:3 Final Cut (10)
128:3 Final Cut (13)
129:3 Final Cut (16)
130:3 Final Cut (19)
131:3 Final Cut (22)
132:3 Final Cut (25)
133:3 Final Cut (28)
134:2 Final Cut (30), 1 Blade Fury (2)
135:3 Blade Fury (5)
136:3 Blade Fury (8)
137:3+1 Blade Fury (12)
138:3 Blade Fury (15)
139:3 Blade Fury (18)
140:3 Blade Fury (21)
141:3 Blade Fury (24)
142:3 Blade Fury (27)
143:3 Blade Fury (30)
144:3 Phantom Blow (4)
145:3 Phantom Blow (7)
146:3 Phantom Blow (10)
147:3 Phantom Blow (13)
148:3 Phantom Blow (16)
149:3 Phantom Blow (19)
150:3 Phantom Blow (22)
151:3 Phantom Blow (25)
152:3 Phantom Blow (28)
153:2 Phantom Blow (30), 1 Thorns (1)
153:3 Thorns (4)
154:3 Thorns (7)
155:3 Thorns (10)
156:3+1 Thorns (14)
157:3 Thorns (17)
158:3 Thorns (20)
159:3 Thorns (23)
160:3 Thorns (26)
161:3 Thorns (29)
162:1 Thorns (30), 1 Maple Warrior (1), 1 Hero’s Will (1)
163:3 Maple Warrior (4)
164:3 Maple Warrior (7)
165:3 Maple Warrior (10)
166:3 Maple Warrior (13)
167:3 Maple Warrior (16)
168:3 Maple Warrior (19)
169:3 Maple Warrior (22)
170:3 Maple Warrior (25)
171:3 Maple Warrior (28)
172:2 Maple Warrior (30), 1 Venom (2)
173:3 Venom (5)
174:3 Venom (8)
175:3 Venom (11)
176:3 Venom (14)
177:3 Venom (17)
178:3 Venom (20)
179:3 Venom (23)
180:3 Venom (26)
181:3 Venom (29)
182:1 Venom (30), 2 Mirrored Target (3)
183:3 Mirrored Target (6)
184:3 Mirrored Target (9)
185:3 Mirrored Target (12)
186:3 Mirrored Target (15)
187:3 Mirrored Target (18)
188:3 Mirrored Target (21)
189:3 Mirrored Target (24)
190:3 Mirrored Target (27)
191:3 Mirrored Target (30)
192:3 Hero’s Will (4)
193:1 Hero’s Will (5), 2 Monster Bomb (2)
194:3 Monster Bomb (5)
195:3 Monster Bomb (8)
196:3 Monster Bomb (11)
197:3 Monster Bomb (14)
198:3 Monster Bomb (17)
199:3 Monster Bomb (20)
200:3 Monster Bomb (23)

Big Bang:

Spoiler!

1st Job:

Spoiler!

10:1 Double Stab (1)
11:3 Double Stab (4)
12:3 Double Stab (7)
13:3 Double Stab (10)
14:Save (3)
15:Save (6)
16:Save (9)
17:Save (12)
18:Save (15)
19:Save (18)
There's nothing else you need in 1st job for the time being, putting points anywhere else would just make it take you longer to level your 2nd and 2nd+ job skills.

2nd Job:

Spoiler!

20:10 Triple Stab (10), 5 Katara Mastery (5), 6 Katara Booster (6)
21:3 Katara Mastery (8)
22:3 Katara Mastery (11)
23:3 Katara Mastery (14)
24:3 Katara Mastery (17)
25:3 Katara Mastery (20)
26:3 Katara Booster (9)
27:3 Katara Booster (12)
28:3 Katara Booster (15)
29:3 Katara Booster (18)
30:2 Katara Booster (20), 1 Disorder (1)
I'm just one of those people that prefer 20 Mastery over 19, so feel free to keep Mastery at 19 and put the point elsewhere.

2nd+ Job:

Spoiler!

30: 1 Slash Storm (1)
31:2 Self-Haste (2), 1 Fatal Blow (1)
32:3 Self-Haste (5)
33:3 Self-Haste (8)
34:3 Self-Haste (11)
35:3 Self-Haste (14)
36:3 Self-Haste (17)
37:3 Self-Haste (20)
38:3 Slash Storm (4)
39:3+1 Slash Storm (8)
40:3 Slash Storm (11)
41:3 Slash Storm (14)
42:3 Slash Storm (17)
43:3 Slash Storm (20)
44:3 Fatal Blow (4)
45:3 Fatal Blow (7)
46:3 Fatal Blow (10)
47:3 Fatal Blow (13)
48:3 Fatal Blow (16)
49:3 Fatal Blow (19)
50:3 Fatal Blow (22)
51:3 Fatal Blow (25)
52:3 Fatal Blow (28)
53:2 Fatal Blow (30), 1 Disorder (2)
54:1 Disorder (3), 2 Dark Sight (2)
55:3 Dark Sight (5)
Alright, well, Self-Haste first since Triple Stab is a pretty strong skill in itself and outdamages Fatal Blow if you're attacking 2-3 mobs and outdamages Slash Storm if you're attacking 1-4 mobs (Triple Stab can't hit 4 monsters at a time, but it'd still be better to use it instead of Slash Storm if there are 4).
Slash Storm and Fatal Blow can be switched around, that order is entirely up to you. After that, max out Booster to macro with Haste, then finish up 2nd+ with Dark Sight so you can have it maxed by the time you have Advanced Dark Sight. I didn't max Shadow Resistance here because with the amount of HP you'll have at this point, it'll make a very miniscule difference and you most likely won't be coming into too much interaction with status effects that you'll need to "resist". I have you max it late in 3rd+ job, just before you would begin to start doing any bossing as an attacker.

3rd Job:

Spoiler!

56:1 Flash Jump (1), 1 Tornado Spin (1), 1 Flashbang (1)
57:3 Flash Jump (4)
58:3 Flash Jump (7)
59:3 Flash Jump (10)
60:3 Flash Jump (13)
61:3 Flash Jump (16)
62:3 Flash Jump (19)
63:1 Flash Jump (20), 2 Dark Sight (7)
64:3 Dark Sight (10)
65:Save (3)
66:Save (6)
67:Save (9)
68:Save (12)
69:Save (15)
70:Save (18)
Alright, well, one of each at 56 to mess around with, then max Flash Jump for obvious reasons. Once you've done that, max out Dark Sight in preparation for Advanced Dark Sight. After that, save your points until 3rd+ because neither Flashbang nor Tornado Spin are worth losing out on getting your 3rd+ skills a high level early on.

3rd+ Job:

Spoiler!

70:5 Bloody Storm (5), 1 Mirror Image (1), 1 Advanced Dark Sight (1), 1 Owl Spirit (1), 1 Upper Stab (1), 10+1 Flying Assaulter (11)
71:3 Bloody Storm (8)
72:2 Bloody Storm (10), 1 Mirror Image (2)
73:3 Mirror Image (5)
74:3 Mirror Image (8)
75:2+1 Mirror Image (11), 1 Flying Assaulter (12)
76:3 Flying Assaulter (15)
77:3 Flying Assaulter (18)
78:2 Flying Assaulter (20), 1 Tornado Spin (2)
79:3+1 Tornado Spin (6)
80:3 Tornado Spin (9)
81:3 Tornado Spin (12)
82:3 Tornado Spin (15)
83:3 Tornado Spin (18)
84:2 Tornado Spin (20), 1 Upper Stab (2)
85:3 Upper Stab (5)
86:3 Upper Stab (8)
87:3 Upper Stab (11)
88:3 Upper Stab (14)
89:3 Upper Stab (17)
90:3 Upper Stab (20)
91:3 Mirror Image (14)
92:3 Mirror Image (17)
93:3 Mirror Image (20)
94:3 Mirror Image (23)
95:3 Mirror Image (26)
96:3 Mirror Image (29)
97:1 Mirror Image (30), 2 Advanced Dark Sight (3)
98:3 Advanced Dark Sight (6)
99:3 Advanced Dark Sight (9)
100:3 Advanced Dark Sight (12)
101:3 Advanced Dark Sight (15)
102:3 Advanced Dark Sight (18)
103:2 Advanced Dark Sight (20), 1 Shadow Resistance (1)
104:3 Shadow Resistance (4)
105:3 Shadow Resistance (7)
106:3 Shadow Resistance (10)
107:3 Shadow Resistance (13)
108:3 Shadow Resistance (16)
109:3 Shadow Resistance (19)
110:1 Shadow Resistance (20), 2 Flashbang (3)
111:3 Flashbang (6)
112:3 Flashbang (9)
113:3 Flashbang (12)
114:3 Flashbang (15)
115:3 Flashbang (18)
116:2 Flashbang (20), 1 Nimble Body (1)
117:3 Nimble Body (4)
118:3 Nimble Body (7)
119:3 Nimble Body (10)
120:3 Nimble Body (13)
You're probably going to want 1 of each skill at the beginning, so go ahead and do that. Next, Flying Assaulter is your main attacking/mobbing move while training. Once you've done that, max Bloody Storm so you can chain it with Flying Assaulter. It's really nice and gives you full invincibility with both skills chained right. After that, Mirror Image at 11 has it hitting 41% compared to level 10's 30%, and it's the biggest jump in damage you're getting, so leave it at that for a while. Now it's time to finish up Flying Assaulter so it attacks 8 mobs just like Bloody Storm. Next, get Tornado Spin maxed as your other chain move with Flying Assaulter. The main difference between Tornado Spin and Bloody Storm is that TSpin rushes, while Storm doesn't. Time for Upper Stab. It is a very useful skill for both it's extra damage after launch and the fact that it is extremely fast. It's also a really good fininsher to spam after using FA+BS/TS combo. At this point, you've got all your main attack skills maxed out, so finish up Mirror Image to bring up your damage. I find Owl Dead an overall useless skill due to it's low damage, cooldown, single target, and its effect only activating when you OHKO a monster with the skill's own effect. The effect doesn't even last a long time anyways, it'll be about 10-15 seconds at max level, and nearly useless at bosses. So just leave it at 1, max out Advanced Dark Sight, Shadow Resistance, and Flash Bang. Flash Bang does work on bosses, which makes it extremely useful. -85% Accuracy at max level pretty much leaves you invincible for the 20 seconds it's in effect.

4th Job:

Spoiler!

120:1 Final Cut (1), 1 Mirrored Target (1), 1 Thorns (1)
121:1 Sudden Raid (1), 1 Venom (1), 1 Chains of Hell (1)
These are your first few basic skills. Final Cut's and Mirrored Target's passive effects are great and are definitely worth the 1 point into them.
Training Build:

Spoiler!

122:3 Final Cut (4)
123:3 Final Cut (7)
124:3 Final Cut (10)
125:3 Final Cut (13)
126:3 Final Cut (16)
127:3 Final Cut (19)
128:3 Final Cut (22)
129:3 Final Cut (25)
130:3 Final Cut (28)
131:2 Final Cut (30), 1 Thorns (2)
132:3 Thorns (5)
133:3 Thorns (8)
134:3 Thorns (11)
135:3 Thorns (14)
136:3 Thorns (17)
137:3 Thorns (20)
138:3 Thorns (23)
139:3 Thorns (26)
140:3 Thorns (29)
141:1 Thorns (30), 2 Venom (3)
142:3 Venom (6)
143:3 Venom (9)
144:3 Venom (12)
145:3 Venom (15)
146:3 Venom (18)
147:3 Venom (21)
148:3 Venom (24)
149:3 Venom (27)
150:3 Venom (30)
Final Cut's passive increases the damage of a few of your other skills, which will be really helpful. Thorns increases Crit Rate, and Venom gives passive damage to the mobs, which is useful with their massive HP. Not really much of a training build, but eh.

Bossing Build:

Spoiler!

122:3 Chains of Hell (4)
123:3 Chains of Hell (7)
124:3 Chains of Hell (10)
125:3 Chains of Hell (13)
126:3 Chains of Hell (16)
127:3 Chains of Hell (19)
128:3 Chains of Hell (22)
129:3 Chains of Hell (25)
130:3 Chains of Hell (28)
131:2 Chains of Hell (30), 1 Venom (2)
132:3 Venom (5)
133:3 Venom (8)
134:3 Venom (11)
135:3 Venom (14)
136:3 Venom (17)
137:3 Venom (20)
138:3 Venom (23)
139:3 Venom (26)
140:3 Venom (29)
141:1 Venom (30), 2 Final Cut (3)
142:3 Final Cut (6)
143:3 Final Cut (9)
144:3 Final Cut (12)
145:3 Final Cut (15)
146:3 Final Cut (18)
147:3 Final Cut (21)
148:3 Final Cut (24)
149:3 Final Cut (27)
150:3 Final Cut (30)
Chains of Hell is one of, if not the, best single target skills in the game. Final Cut doubles your damage at max level and also does a lot of initial damage. Venom's passive damage will build up a fair bit and will build up fairly nicely.
Training-wise, you'll be a bit slower without the passive effects from Final Cut early on and no Thorns..

All-rounder Build:

Spoiler!

122:3 Thorns (4)
123:3 Thorns (7)
124:3 Thorns (10)
125:3 Thorns (13)
126:3 Thorns (16)
127:3 Thorns (19)
128:3 Thorns (22)
129:3 Thorns (25)
130:3 Thorns (28)
131:2 Thorns (30), 1 Final Cut (2)
132:3 Final Cut (5)
133:3 Final Cut (8)
134:3 Final Cut (11)
135:3 Final Cut (14)
136:3 Final Cut (17)
137:3 Final Cut (20)
138:3 Final Cut (23)
139:3 Final Cut (26)
140:3 Final Cut (29)
141:1 Final Cut (30), 2 Maple Warrior (2)
142:3 Maple Warrior (5)
143:3 Maple Warrior (8)
144:3 Maple Warrior (11)
145:3 Maple Warrior (14)
146:3 Maple Warrior (17)
147:3 Maple Warrior (20)
148:3 Maple Warrior (23)
149:3 Maple Warrior (26)
150:3 Maple Warrior (29)
151:1 Maple Warrior (30)
Final Cut is good for both training and bossing, as is Thorns and Maple Warrior. The damage boosts you get from them increase your damage in any and all situations.

Skill DPS Calculations :

Spoiler!

*Note 1: Calculations are only applicable for Post-Chaos. Big Bang and earlier versions still have split Dagger and Katara ranges.
*Note 2: DPS is calculated assuming Booster is in effect.
*Note 3: Calculations are raw DPS, PDRate is not taken into account.
Double Stab

Spoiler!

Level	Skill Damage	DPS
1	146%	243.33%
2	152%	253.33%
3	158%	263.33%
4	164%	273.33%
5	170%	283.33%
6	176%	293.33%
7	182%	303.33%
8	188%	313.33%
9	194%	323.33%
10	200%	333.33%
11	206%	343.33%
12	212%	353.33%
13	218%	363.33%
14	224%	373.33%
15	230%	383.33%
16	236%	393.33%
17	242%	403.33%
18	248%	413.33%
19	254%	423.33%
20	260%	433.33%

Triple Stab

Spoiler!

Level	Skill Damage	DPS per Mob	Total DPS
1	249%	377.27%	754.55%
2	258%	390.91%	781.82%
3	267%	404.55%	809.09%
4	276%	418.18%	836.36%
5	285%	431.82%	863.64%
6	294%	445.46%	890.91%
7	303%	459.09%	918.18%
8	312%	472.73%	945.46%
9	321%	486.36%	972.73%
10	330%	500%	1000%

Fatal Blow

Spoiler!

Level	Skill Damage	DPS
1	448%	373.33%
2	456%	380%
3	464%	386.67%
4	472%	393.33%
5	480%	400%
6	488%	406.67%
7	496%	413.33%
8	504%	420%
9	512%	426.67%
10	520%	433.33%
11	528%	440%
12	536%	446.67%
13	544%	453.33%
14	552%	460%
15	560%	466.67%
16	568%	473.33%
17	576%	480%
18	584%	486.67%
19	592%	493.33%
20	600%	500%
21	608%	506.67%
22	616%	513.33%
23	624%	520%
24	632%	526.67%
25	640%	533.33%
26	648%	540%
27	656%	546.67%
28	664%	553.33%
29	672%	560%
30	680%	566.67%

Upper Stab

Spoiler!

*Note: Does not include the airborne damage bonus.

Level	Skill Damage	DPS per Mob	Total DPS
1	202%	561.11%	2244.44%
2	204%	566.67%	2266.67%
3	206%	572.22%	2288.89%
4	208%	577.78%	2311.11%
5	210%	583.33%	2333.33%
6	212%	588.89%	2355.56%
7	214%	594.44%	2377.78%
8	216%	600%	2400%
9	218%	605.56%	2422.22%
10	220%	611.11%	3055.56%
11	222%	616.67%	3083.33%
12	224%	622.22%	3111.11%
13	226%	627.78%	3138.89%
14	228%	633.33%	3166.67%
15	230%	638.89%	3194.44%
16	232%	644.44%	3222.22%
17	234%	650%	3250%
18	236%	655.56%	3277.78%
19	238%	661.11%	3305.56%
20	240%	666.67%	4000%

Blade Fury

Spoiler!

Level	Skill Damage	DPS per Mob	Total DPS	DPS with Mirror Image	Total DPS with Mirror Image
1	408%	680%	2040%	1156%	3468%
2	411%	685%	2055%	1164.5%	3493.5%
3	414%	690%	2070%	1173%	3519%
4	417%	695%	2085%	1181.5%	3544.5%
5	420%	700%	2100%	1190%	3570%
6	423%	705%	2115%	1198.5%	3595.%
7	426%	710%	2130%	1207%	3621%
8	429%	715%	2145%	1215.5%	3646.5%
9	432%	720%	2160%	1224%	3672%
10	435%	725%	2900%	1232.5%	4930%
11	438%	730%	2920%	1241%	4964%
12	441%	735%	2940%	1249.5%	4998%
13	444%	740%	2960%	1258%	5032%
14	447%	745%	2980%	1266.5%	5066%
15	450%	750%	3000%	1275%	5100%
16	453%	755%	3020%	1283.5%	5134%
17	456%	760%	3040%	1292%	5168%
18	459%	765%	3060%	1300.5%	5202%
19	462%	770%	3080%	1309%	5236%
20	465%	775%	3875%	1317.5%	6587.5%
21	468%	780%	3900%	1326%	6630%
22	471%	785%	3925%	1334.5%	6672.5%
23	474%	790%	3950%	1343%	6715%
24	477%	795%	3975%	1351.5%	6757.5%
25	480%	800%	4000%	1360%	6800%
26	483%	805%	4025%	1368.5%	6842.5%
27	486%	810%	4050%	1377%	6885%
28	489%	815%	4075%	1385.5%	6927.5%
29	492%	820%	4100%	1394%	6970%
30	495%	825%	4950%	1402.5%	8415%

Phantom Blow

Spoiler!

*Note: DPS does not include the Ignore PDRate that is inherent to Phantom Blow.

Level	Skill Damage	DPS	DPS with Mirror Image
1	456%	760%	1292%
2	462%	770%	1309%
3	468%	780%	1326%
4	474%	790%	1343%
5	480%	800%	1360%
6	486%	810%	1377%
7	492%	820%	1394%
8	498%	830%	1411%
9	605%	840%	1428%
10	510%	850%	1445%
11	516%	860%	1462%
12	522%	870%	1479%
13	528%	880%	1496%
14	534%	890%	1513%
15	540%	900%	1530%
16	546%	910%	1547%
17	552%	920%	1564%
18	528%	930%	1581%
19	564%	940%	1598%
20	570%	950%	1615%
21	576%	960%	1632%
22	582%	970%	1649%
23	588%	980%	1666%
24	594%	990%	1683%
25	600%	1000%	1700%
26	606%	1010%	1717%
27	612%	1020%	1734%
28	618%	1030%	1751%
29	624%	1040%	1768%
30	630%	1050%	1785%

Training Locations :

Spoiler!

1-10 : Maple Island
10-20 : Dual Blade Storyline Quests
20-30 : Victoria Island
30-40 : Victoria/Orbis
40-50 : Orbis/El Nath/Zipangu
50-60 : Orbis/El Nath/Zipangu/Ludibrium
60-70 : Zipangu/Ludibrium/Omega Sector/Korean Folk Town
70-80 : Wind Raiders/Ariant
80-90 : Ariant/Magatia/Mu Lung/Storm Breakers
90-100 : Galloperas/Night Shadows/Dreamy Ghosts/Elderwraiths/Herb Town
100-110 : Galloperas/Night Shadows/Krus/Captains
110-120 : Deep Ludi/Leafre
120-130 : Leafre/Deep Ludi/El Nath Dungeon/Lion Heart Castle
130-140 : El Nath Dungeon/Leafre/Bains/Lion Heart Castle
140-160 : Leafre/Temple of Time/Lion Heart Castle
160+ : Lion Heart Castle/Future Henesys

Credits to Fiel of Southperry for Skill info and myself for this guide.