Guild Ability Information
 

The following information is from Vamp's study of penalties in a previous beta of the game.(Infinite Worlds)

Here are listed the abilities of Warrior (best in Critical Hit, Fighting), Thief (best in Thieving, Backstabbing), Explorer (best in Perception), Warlock (best in Language), and Ninja (best in Multi Swing). All abilities are based on Dwarf and Human (for Ninja only), with maxed stats, but no item equipped.  Stats affect only thieving, perception & language ability.  Exactly HOW they affect the abilities is unknown.

Warrior
Level
Critical Hit
Multiple Swing
Fighting
1
0
0
14
50
7
6
28
100
13
11
38
150
20
17
47
200
26
21
53
300
38
31
63
400
49
40
72
500
59
48
79
700
77
62
89
999
100
82
100

Thief
Level
Thieving
Backstab
1
24
0
50
42
7
100
50
14
150
55
20
200
60
26
300
67
38
400
72
49
500
77
59
700
85
77
999
95
100

Explorer
Level
Critical Hit
Fighting
Perception
1
5
13
 
50
4
19
77
100
8
23
84
150
12
27
88
200
16
33
91
300
23
37
95
400
29
41
98
500
35
43
101
700
46
47
104
999
60
53
108

Warlock
 
Ninja
Level
Language
 
Thieving
Backstab
Critical Hit
Multiple Swings
Fighting
1
27
 
16
0
0
0
8
50
40
 
30
3
5
7
17
100
47
 
36
7
11
14
25
150
51
 
40
10
16
20
30
200
54
 
44
13
20
26
36
300
59
 
49
18
29
37
42
400
63
 
53
23
38
49
48
500
67
 
57
28
46
59
52
700
73
 
64
37
60
77
59
999
79
 
71
48
78
100
67
 

Finally, here is when guilds get their extra swings.

Extra Swings Levels
Guild
1st Extra
2nd Extra
3rd Extra
4th Extra
5th Extra 
Ninja
28
60
131
287
629
Warrior
46
162
578
-
-
Paladin
50
192
??
-
-
Villain
53
243
800(?)
-
-
Barbarian
59
268
-
-
-
3rd Swing for villain is uncertain, but '-' indicated I am fairly certain that guild does not get this number of extra swings.

Therefore, if you want extra swings, then the ninja's guild is really your only option. Three extra swings before warrior(who is next best) even gets their second completely blitzes all competition. I doubt that any other guild will get a 4th extra swing, and most guilds will get their 3rd extra swing at very high levels.