I’d like to see NPC “personalities” as a sort of composition for NPC behaviors where you can stack different decision making engines for NPCs. The “guard” personality says to stay in one area or follow a certain patrol route or character, to prefer higher defense armor, and to be extra vigilant. The “fighter” personality says to aggressively chase targets, prefer direct approaches, and to prefer armor balanced between encumbrance and defense. The “scavenger” personality could say to avoid combat unless very opportunistic situation, prefer sneaking and quiet weapons, and to select armor with low encumbrance. The “diplomat” personality would prefer to talk their way out of situations and negotiate for or purchase protection. Then, there could be a “bandit” personality that dictates that the NPC with that personality prefers violence and intimidation, and will attack other unaligned humans unprovoked.
NPCs can have multiple personalities that stack, so an NPC with both “bandit” and “guard” personalities will use both sets of rules to make decisions. A priority system could be used to resolve conflicts, so a “diplomat” “scavenger” “bandit” NPC might try to convince you they are friendly, then stab you in the back when they get the chance.
On the player control side of things, there could be job type personalities, like a “foreman” personality that can be assigned to a friendly NPC that has a certain set of stats or skills (construction 5+, fabrication 3+, for example) and NPCs with that personality can direct you to acquire materials and when things get more advanced, command other NPCs to build things. Followers could have a set of personalities that govern how much they trust the player and how much the player can command them to do, like the basic “follower” personality means they’re just tagging along with you. If you run into a sticky situation, their other personalities will govern how they respond. If you build trust, they can be upgraded to a “companion” personality and you can instruct them to do more things like guard a location, get more detail about their skills/stats, and so on. Finally, if you build up more trust, they can be upgraded to the “partner” personality where you can dictate what gear they wear and what weapons they use and so on.
Most personalities should be presets that can’t be changed, but the player should also have the ability to define their own personalities by assigning sets of rules to an NPC or saving that set as a preset and then assigning that preset to an NPC. Certain personality rules might require another personality be active, that the NPC has a certain level of stats or skills, or the player has a certain level of stats or skills. For example, if you want to create a “medic” personality and assign it to an NPC, you might set a rule that says to use healing supplies on any nearby NPC or the player whenever they have a body part that is at 60% or below, which might require the NPC to have a first aid of at least 3, and a trust level of at least “companion”. If you wanted to create a “martyr” personality and direct the NPC to attack aggressively even against a much more powerful enemy, it might require that you have “partner” level trust and that the player has a speech skill of 6 or higher.
Some rule examples:
Combat:
[ul][li]Always attack aggressively[/li]
[li]Attack when convenient[/li]
[li]Attack my target only[/li]
[li]Defend yourself when attacked[/li]
[li]Flee when attacked[/li][/ul]
Armor:
[ul][li]Maximize defense[/li]
[li]Maximize storage[/li]
[li]Minimize encumbrance[/li]
[li]Balance encumbrance/defense[/li]
[li]Balance encumbrance/storage[/li]
[li]Balance defense/storage[/li]
[li]Specific clothing only[/li][/ul]
- NPCs should always try to prioritize warmth if they are in danger of frostbite
Item Pickups:
[ul][li]Strictly items needed for survival and direct upgrades of current gear[/li]
[li]Construction and crafting supplies[/li]
[li]Weapons and ammo[/li]
[li]Tech/electronics[/li]
[li]First aid[/li]
[li]Armor/clothing[/li]
[li]Nothing[/li][/ul]
Healing Items:
[ul][li]Heal any friendlies when a body part health drops below X%[/li]
[li]Heal player only when a body part health drops below X%[/li]
[li]Do not use any healing supplies except on self[/li][/ul]
- NPCs should almost always health themselves whenever needed
Weapon Priority:
[ul][li]Use best weapon for current skills[/li]
[li]Prefer bashing[/li]
[li]Prefer cutting[/li]
[li]Prefer ranged[/li]
[li]Prefer silent[/li]
[li]Prefer heavy[/li]
[li]Prefer explosives[/li]
[li]Prefer electronic/advanced[/li]
[li]Prefer fiery[/li]
[li]Use designated weapon only[/li][/ul]
Engagement and Targeting:
[ul][li]May initiate combat[/li]
[li]Only join combat in progress[/li]
[li]Avoid targets that may damage friendlies (auto fire weapons, flamethrowers, grenades)[/li]
[li]Target most injured enemy[/li]
[li]Target player’s target[/li][/ul]
There are probably many, many, many more rules and lots of potential personalities.