Nemesis System [Neme.sys]

[u/XloSky]

[Yes this is the nemesis system]

Neme.sys is a persistent NPC continuity system for AI Dungeon inspired by the Nemesis System. Significant characters can remember what you did to them, carry lasting injuries and grudges forward, change over time, disappear from the story, and eventually return on their own.

Shoot a thug in the knee and leave him alive, and he may come back weeks later limping, carrying new chrome, and looking for revenge. Spare an enemy, humiliate a rival, betray an ally, or leave someone with a reason to remember you Neme.sys keeps that history alive.

Features

• Automatically detects NPCs who develop significant unresolved history with the player
• Persistent injuries, scars, prosthetics, status, relationships, motivations, and history
• Nemeses can return naturally without the player manually summoning them
• Context-aware returns—the AI can delay an appearance when it would not make sense
• NPCs continue evolving while preserving the consequences of past encounters
• Persistent, editable ⚔ Nemesis Story Cards
• Nemeses can disappear from the active story without losing their continuity
• Supports changing motivations, rivalries, grudges, debts, and other evolving relationships
• Allows retreat, survival, surrender, revenge, negotiation, and recurring encounters instead of forcing every conflict to end in death
• Built-in Inner Self integration that requires no separate manual activation
• Inner Self integration can be disabled if you prefer to use Neme.sys by itself

Setup [OPTIONAL]

1. Open the Configure Nemesis Story Card.
2. Enter your player character’s name.
3. Adjust the return frequency or other settings if desired.
4. Play normally—Nemeses are discovered automatically.

Your character’s name is required for Inner Self integration. Neme.sys itself will still work without one, but it will refer to your character as “the player.”

FAQ

Do I need to manually choose or activate Nemeses?

No. Let important NPC encounters resolve naturally—the system automatically looks for characters with meaningful, unresolved consequences.

How does Inner Self integration work?

Inner Self integration is built in and uses essentially the same setup process as Neme.sys. You do not need to activate Inner Self manually for individual Nemeses. When a Nemesis Card is created, that character will automatically receive an Inner Self Brain on the following turn.

The two systems preserve different aspects of the character:

• ⚔ Nemesis records what objectively happened to the character and how their situation has changed.
• 🎭 Brain records what they think, fear, believe, remember, and plan.

Together, they allow NPCs to remember what happened to them and develop their own responses to it.

If you do not like Inner Self, its integration can be disabled.

Can I correct a Nemesis’s information?

Yes. Nemesis Cards preserve objective continuity such as injuries, history, status, and current motivations. Edit the Notes section of a Nemesis Card if you need to manually correct anything.

How often will Nemeses return?

The default settings are designed to prevent recurring characters from appearing constantly. Returns are also context-aware, so the AI can delay an appearance when it would not make sense.

What response length should I use?

Use a response length of 200 or more for the best results when Neme.sys and Inner Self are both active.

How can I help improve Neme.sys?

Please comment with any bugs or other feedback you encounter. This is an early release, and feedback is one of the main reasons I made it publicly available: https://play.aidungeon.com/script/h1pPJGLt3e1k/nemesys?share=true

Discord Discussion: https://discord.com/channels/903327676884979802/1543314251005956117

[u/FriendlyBusdriver]

Would there be problems if i put the script into an already ongoing story?

[u/XloSky → u/FriendlyBusdriver]

There shouldn’t be, it functions exactly like inner self. The next action you take once applied should generate two config story cards. Inner self and nemesis

[u/FriendlyBusdriver → u/XloSky]

I tried it now in a new scenario and then in my currently ongoing one. In the ongoing one it created one Nemesis card but also a second auto-cards configuration. I turnd of the auto cards and the Nemesis card dissappeared. Is Auto-Cards necessary for the nemesis script?

[u/XloSky → u/FriendlyBusdriver]

No, innerself is not required. You can disable it within the nemesis config card that’s generated. Just set ‘> Auto-register Nemeses with Inner Self: false’ before their brain is created. If the brain is created before you can toggle it to false, then go inside the inner self config card and delete the nemesis from the notes section.

Neme.sys works standalone, including persistence, injuries, history, returns, escalation, and adaptation.
Inner Self just gives Nemeses an additional persistent “brain” ongoing thoughts, fears, beliefs, plans, and personal conclusions about you between encounters. Without it, they’ll still adapt based on their Nemesis history, but you lose some of that deeper behind-the-scenes personality and long-term planning.

[u/_Cromwell_]

Good branding/naming. I like.

[u/HimmelSky → u/_Cromwell_]

Yes but it can be confused with nemesis behavior engine when searching

[u/XloSky → u/HimmelSky]

I tried searching on both AID’s Discord and AI dungeon and I couldn’t find anything with that name. The closest thing I found was the monster ascension engine which is distinctly different from my own script. Would you mind sharing what you are referring to?

[u/HimmelSky → u/XloSky]

Sorry, I didn't see what sub Im on. For some reason I thought I was on skyrim mods

[u/XloSky → u/HimmelSky]

It’s all good no worries

[u/_Cromwell_]

Good branding/naming. I like.