Combat Tables

From OSE SRD

These tables list the attack probabilities for all monsters and characters and the saving throw values used by monsters and normal humans.

PC and NPC Saving Throws

PCs and classed NPCs use the saving throw tables for their character class, listed in the genre rules book.

Normal Humans

All humans who are not a member of an adventuring class are classified as normal humans. They are treated as having less than 1 Hit Die and have their own saving throw and attack probabilities.

Attack Matrix by THAC0

Attack Roll to Hit AC
THAC0 –3 –2 –1
0
1
2
3
4
5
6
7
8
9
20 [–1]
20
20
20
20
19
18
17
16
15
14
13
12
11
19 [0]
20
20
20
19
18
17
16
15
14
13
12
11
10
18 [+1]
20
20
19
18
17
16
15
14
13
12
11
10
9
17 [+2]
20
19
18
17
16
15
14
13
12
11
10
9
8
16 [+3]
19
18
17
16
15
14
13
12
11
10
9
8
7
15 [+4]
18
17
16
15
14
13
12
11
10
9
8
7
6
14 [+5]
17
16
15
14
13
12
11
10
9
8
7
6
5
13 [+6]
16
15
14
13
12
11
10
9
8
7
6
5
4
12 [+7]
15
14
13
12
11
10
9
8
7
6
5
4
3
11 [+8]
14
13
12
11
10
9
8
7
6
5
4
3
2
10 [+9]
13
12
11
10
9
8
7
6
5
4
3
2
2
9 [+10]
12
11
10
9
8
7
6
5
4
3
2
2
2
8 [+11]
11
10
9
8
7
6
5
4
3
2
2
2
2
7 [+12]
10
9
8
7
6
5
4
3
2
2
2
2
2
6 [+13]
9
8
7
6
5
4
3
2
2
2
2
2
2
5 [+14]
8
7
6
5
4
3
2
2
2
2
2
2
2


Monster Saving Throws

Hit Dice Death Wands Paralysis Breath Spells
Normal Human
14
15
16
17
18
1–3
12
13
14
15
16
4–6
10
11
12
13
14
7–9
8
9
10
10
12
10–12
6
7
8
8
10
13–15
4
5
6
5
8
16–18
2
3
4
3
6
19–21
2
2
2
2
4
22 or more
2
2
2
2
2


Monster THAC0 by Hit Dice

Hit Dice THAC0
Normal Human 20 [–1]
Up to 1 19 [0]
1+ to 2 18 [+1]
2+ to 3 17 [+2]
3+ to 4 16 [+3]
4+ to 5 15 [+4]
5+ to 6 14 [+5]
6+ to 7 13 [+6]
7+ to 9 12 [+7]
9+ to 11 11 [+8]
11+ to 13 10 [+9]
13+ to 15 9 [+10]
15+ to 17 8 [+11]
17+ to 19 7 [+12]
19+ to 21 6 [+13]
21+ or more 5 [+14]

Attack Rolls Using THAC0 (Optional Rule)

Instead of referring to the attack matrix, attacks may be resolved using THAC0 directly. A THAC0 score denotes the attack roll required to hit AC 0. The attack roll required to hit opponents of other AC scores can be calculated by subtracting the target AC from the THAC0. For example, a character with a THAC0 of 19 could hit an opponent with AC 5 on a roll of 14 or greater (19 – 5 = 14).

Note: Using THAC0 to resolve attack rolls results in very slightly different attack probabilities than when using the traditional approach of referring to the attack matrix.