This very simple method of randomly determining personality type for NPCs is based on the 7 Deadly Sins and their Opposing Virtues. Simply roll 3d6 for each of the categories shown below to determine the personality for your NPC. A score of 10 or 11 is essentially neutral, with no meaningful tendency either way.
As with any random determination system, any element which is actually important to the campaign should be determined by the GM, leaving random selection only for unimportant stuff. Personally, I tend to use it mostly to spark ideas rather than as an end in itself, and will happily ignore the dice if they don't give me the result I want.
| PRIDE | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11—10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | HUMILITY |
| SPITE | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11—10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | KINDNESS |
| GLUTTONY | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11—10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | ABSTINENCE |
| LUST | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11—10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | CHASTITY |
| WRATH | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11—10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | PATIENCE |
| AVARICE | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11—10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | GENEROSITY |
| SLOTH | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11—10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | DILIGENCE |
You have an NPC, Wulfstan, a small-time tribal chieftain into whose lands the PCs have stumbled on their way home from looting some temple or other of all its wealth. How is he likely to react to the appearance of a group of battle-weary but wealthy strangers?
We roll 3d6 7 times and get 11, 15, 6, 12, 10, 16, and 11.
| WULFSTAN'S PERSONALITY PROFILE | |||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PRIDE | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11—10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | HUMILITY | |
| SPITE | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11—10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | KINDNESS | |
| GLUTTONY | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11—10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | ABSTINENCE | |
| LUST | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11—10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | CHASTITY | |
| WRATH | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11—10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | PATIENCE | |
| AVARICE | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11—10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | GENEROSITY | |
| SLOTH | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11—10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | DILIGENCE | |
Wulfstan has few virtues; in fact just one: he is no glutton. However, he is spiteful and avaricious, and has just a touch of lustfulness. He will almost certainly try to get the PCs' treasure for his own, and he isn't above using treachery to do it. He might try a spot of seduction, but probably not if it would hinder his chances of nicking the loot — his ABSTINENCE rating indicates that he's a man accustomed to self-denial to get the things that he wants.
Considering the results of our random determination of his personality, there's a pretty good chance that our petty chieftain is called something like "Wulfstan the Greedy" or "Wulfstan Two-Faced". He's really not a very nice guy.
Two other personality categories immediately spring to mind:
No doubt there may be others which might be more or less relevant to one's specific campaign. However, I think the sins and virtues cover most of the bases, and adding too many more would probably add needless complexity. Heck, if you really wanted to get ultra-simple you could probably whittle it down to just one.... NAUGHTY vs. NICE :)