Evolving NPC Personality and Love System

The purpose of this system is to create personality for NPCs, primarily for solo play and an optional mechanic for letting such NPCs fall in love with PCs (it is assumed that the player decides if their PC falls in love). If the love and romance aspect is of no interest to you, you can still use the system as a way of getting to know NPCs through interactions. It is system and setting agnostic, so feel free to use it with any game you want. This system is based on the personality apsects of my NPC Generator.

Background to the love aspect

In some traditional computer dating games, the mechanic by which NPCs fall in love with the PC is that the player tries to find out what the NPCs like, and then gives that to them. In games like Stardew Valley, this often takes the form of figuring out what your NPC love interest's favorite object is, and then giving them a bunch of that object until they fall in love with you (yeah, it makes no sense to me either). In other games, you figure out what type of partner your love interest prefers and then you pretend to be that kind of partner (rather than just be yourself) in order to fool the NPC to fall in love with you. This is also highly questionable, and sends really strange messages to inexperienced young players about what love is and how relationships work.

How this system is different

This system is different. The falling in love aspect of this personality system is completely optional but if you do want to use it, it's based on finding someone you're compatible with rather than trying to get into everyone's pants. It is based on five real world personality aspects which define characters. You define the personality of your PC(s) as you see fit using this system, and the personalities of NPCs you come into contact with will gradually evolve randomly as you interact with them. If your personalities happen to be compatible, then love can happen - but it can't be forced.

The evolving personality system

If you've read my NPC Generator, then you will recognize the system. To define a personality, you have to set values for from 1 to 7 for five different personality aspects:

  1. Openness: How open and curious you are.
  2. Conscientiousness: How careful and diligent you are.
  3. Extraversion: How interested you are in interacting with other people.
  4. Agreeableness: How "nice" or benevolent you are.
  5. Neuroticism: How worried or prone to moodiness or depression you are.

Meeting an NPC for the first time

Empty Personality sheet

The NPCs' personality aspect values will not be known to you until your PC(s) have interacted with them for a bit (because you don't generate those numbers until then). One by one, those five numbers will be revealed as PCs and NPCs get to know each other.

When you meet a new NPC, prepare a simple personality sheet for them, but don't add any numbers or descriptors to them yet.

Interacting with NPCs - Personality rolls

On this sheet, we have rolled a 4 on Agreeableness

Once a PC and an NPC have interacted with each other for some time, it's time to make a Personality roll. How often this should be done is up to you, but I'd recommend not rolling more than once (for a specific NPC) every 20 real world minutes, and only after the PC and NPC in question have had time to interact meaningfully.

How to make a Personality roll

1d20 Result
1-3 Agenda revealed
4-5 1
6-7 2
8-9 3
10-11 4
12-13 5
14-15 6
16-17 7
18-20 Perfect match
1d20 Goal Focus Obstacle
1 Aquire Adversary Alliance
2 Avenge Artefact Conflict
3 Betray Beast Conflicting interests
4 Conceal Child Criminal past
5 Conquer Enemy Distance
6 Destroy Idea Duty
7 Discover Knowledge Family
8 Escape Location Forbidden love
9 Expand Love Health
10 Explore Neighbor Honor
11 Gather Other NPC Hostility
12 Glorify Parent Lack of information
13 Infiltrate PC Lack of resources
14 Lead Relationship Law
15 Learn Relative Love
16 Oppose Revenge Mysterious circumstances
17 Prevent Reward Oath
18 Reconcile Ruler Opposing faction
19 Restore Structure Pursuers
20 Worship Wealth Time

If you got the result of "Other NPC" as the Focus, then randomly determine which one of your existing NPCs, or perhaps introduce a new one (which doesn't necessarily mean you have to create it right now).

Once you have the Goal, Focus, and Obstacle you have to figure out what it means, and write it down. For an example of how to do this, check the Agenda section of the NPC Generator.

If we got an agenda instead of a value, that means we're now done with this Personality roll; we learned an agenda of the NPC instead of getting to know an aspect of their personality. You can get another chance to get a value the next time you make a Personality roll for this NPC.

Adding a Descriptor

We got "Polite" as our Descriptor for Agreeableness

If we got a value for one of the Personality aspects (rather than an Agenda), it's time to generate a descriptor for it. This "descriptor" is simply a word which gives a verbal description of that particular aspect of the NPC's personality.

Once the NPC has all five of its values, you can stop doing this. You have now gotten to know this person. But you can still make rolls when you want to know how an NPC will react in a certain situation - see the section Personality rolls of NPCs you already know below.

Openness descriptors

1d4 Openness 1 Openness 2 Openness 3 Openness 4 Openness 5 Openness 6 Openness 7
1 Authoritarian Inflexible Dogmatic Skeptical Unbiased Philosophical Tolerant
2 Intolerant Pessimistic Conservative Resistant Receptive Flexible Progressive
3 Cynical Hard-headed Stubborn Realistic Open-minded Creative Optimistic
4 Narrow-minded Prejudiced Traditional Pragmatic Curious Inquisitive Adventurous

Conscientiousness descriptors

1d4 Consc. 1 Consc. 2 Consc. 3 Consc. 4 Consc. 5 Consc. 6 Consc. 7
1 Negligent Hedonistic Procrastinating Distracted Punctual Disciplined Ambitious
2 Irresponsible Impulsive Impatient Casual Patient Thorough Persevering
3 Careless Disorganized Unorganized Practical Responsible Efficient Methodical
4 Lazy Unreliable Indecisive Diligent Dependable Goal-oriented Perfectionist

Extraversion descriptors

1d4 Extrov. 1 Extrov. 2 Extrov. 3 Extrov. 4 Extrov. 5 Extrov. 6 Extrov. 7
1 Solitary Reserved Submissive Aloof Outgoing Jovial Energetic
2 Reclusive Shy Reflective Contemplative Sociable Cheerful Passionate
3 Private Introspective Quiet Ambivert Expressive Listener Flamboyant
4 Withdrawn Independent Serious Easy-going Lively Bubbly Flirtatious

Agreeableness descriptors

1d4 Agree. 1 Agree. 2 Agree. 3 Agree. 4 Agree. 5 Agree. 6 Agree. 7
1 Cruel Selfish Rude Arrogant Cooperative Kind Humorous
2 Greedy Boastful Sarcastic Argumentative Trusting Caring Forgiving
3 Deceptive Jealous Vain Polite Honest Compassionate Charming
4 Manipulative Cynical Competitive Diplomatic Loyal Generous Altruistic

Neurotisism descriptors

1d4 Neuro. 1 Neuro. 2 Neuro. 3 Neuro. 4 Neuro. 5 Neuro. 6 Neuro. 7
1 Serene Grounded Confident Relaxed Wary Sensitive Insecure
2 Stoic Calm Focused Concerned Tense Irritable Self-critical
3 Hardy Adaptable Stable Restless Anxious Moody Depressed
4 Poised Sensible Resilient Fickle Vulnerable Nervous Panicky

Personality rolls of NPCs you already know

Fully filled out Personality sheet

Personality rolls are not only for getting to know NPCs. They can also be used to check how they react or respond in a specific situation.

To find out how an NPC will act or react to something, use the following procedure:

  1. Decide which personality trait best fits what you're trying to find out. For example, if you want to know if the NPC wants to talk with the players, then NPC's Extraversion is probably the best trait to use.
  2. Formulate a yes/no question such that it includes the some variant of the name of the personality aspect. For example, "Is the NPC extroverted enough to want to talk to the party" is good because it includes a variation of the word "extraversion". However, "Is the NPC reluctant to talk" is bad, since "reluctant to talk" is the opposite of extraverted, so you'd end up with the opposite result of what you want.
  3. Roll 1d8. If the result is less than or equal to the NPC's personality aspect value, then the answer to the question is "yes", otherwise it is "no".
    • If you want to, you can allow the personality aspect value to be temporarily modified for a particular roll. For example, you might want the party's relationship status - or the outcome of a Persuasion roll - to affect it, increasing or decreasing the probability of a positive answer.

The Love system (optional)

Oh, you're interested in the love system, are you? Alright, ya horny bastard (read in Scottish accent for best effect), let's get into it.

If you want to use the Love system, you need to start by creating a personality sheet for your PC before you start playing - the PC needs a number from 1 to 7 for each of the five personality aspects above. The purpose of this is to see if you are "compatible" with the NPCs you meet. You can randomize these values if you want, but my recommendation is that you simply set them to the values you want - in other words, "design" the personality of your PC.

Making Personality rolls with the Love system

Every time you make a Personality roll for an NPC, you compare the NPC's value of that personality aspect (which you may have just generated if it wasn't already known) with the corresponding value for your PC.

What the Love points mean

Love points Meaning
-3 to -2 Dislike
-1 to 0 Uninterested
+1 to +2 Curious
+3 to +4 Interested
+5 to +7 Has a crush
+8 to +10 In love

Courting rolls

What would be the point of love without courting? Once the NPC has taken an interest in your PC, you can start courting by making Courting rolls. There are various kinds of potential Courting rolls, all with different Difficulty classes (DCs). To make a courting roll:

Compare the result to the DC of the activity in question in the below table. If the result of the courting roll is equal to or higher than the DC of the activity in question, then the NPC's answer is yes. If the result is less than the DC, then the NPC loses 1 Love point.

DC Activity
6 Asking the NPC on a date
8 Invite to intimate relations
10 Proposing a relationship
12 Proposing marriage (only if already in relationship)

Going on a date

Intimate relations

Proposing a relationship

If the Courting roll succeeds, then the NPC has agreed to enter a committed relationship with your PC. Once this has happened, you can choose to not use Love points anymore - you have won the love of your partner.

Unless, of course, you want to actually propose?

Proposing a marriage

If your PC and the NPC are already in a relationship, you can make a marriage proposal. If successful, your love accepts your hand in marriage. Unless you want to have the risk of falling out of love (which could be an interesting plot arc in and of itself), you could stop using the Love system once this happens.

Conclusion

One of the reasons why I love the solo RPGs and the TTRPG hobby in general, is that the whole experience is so customizable. Feel free to alter this system to suit your needs (or, ahem, desires). As long as you're having fun, there's no way to play incorrectly in a solo game.

In other words - go play, and have fun!