The idea is that with the mod activated, the player has a constant urge to kill which can only be held off by doing so. This would make it interestingly hard to play a good character, as Kal is always attempting to be. Of course, this is still an idea because of a limitation in Gamebryo. While it is fairly simple to detect if the player kills a certain NPC, it's (afaik) impossible to detect if the player kills any NPC without adding a script to every single one. But nonetheless, here is the idea:
When the player awakes, they find a selection of strange notes in their pip-boy. Soon they develop a growing urge to kill which refuses to go away.
> The player must kill humans regularly in order to stave off psychosis.
> Killing non-humans also works but is much less effective (must be killed more often).
> Blood packs can draw out the onset of psychosis, but is by no means a solution.
> As the player approaches psychosis, they get less communicative (penalty to charisma, intelligence, etc.) and more violent (bonus to strength, endurance, etc.).
> If the player reaches psychosis, they pass out and everyone in the immediate area is killed, regardless of standing towards the player or plot importance (essential characters are still only knocked out).
As the player becomes more aware of the psychosis and, inevitably, kills more people, several perks become available. These perks change how the player reacts to the psychosis and also has permanent effects on the player's karma rating. They are given below in the order they are revealed. All the perks are mutually exclusive.
> I am a monster.
>> The player believes they are evil and the psychosis is a monster within them. They accept their need to kill but still struggle against it.
- Player may no longer achieve the 'Very Good' karma level.
- Approaching-psychosis SPECIAL affects are reduced.
- Blood packs immediately bring the psychosis closer, but then hold it steady for a longer period of time.
- Killing humans (even evil ones) gives a karma penalty.
> I am a nightmare.
>> The player accepts and welcomes the psychosis, believing themselves to be an angel of death or similar.
- Player may no longer achieve the 'Neutral' karma level or higher (always Evil or Very Evil).
- SPECIAL effects are permanent at a reduced level, only the positive ones increase as the psychosis nears.
- Blood packs and killing non-humans have reduced effect.
- Killing humans gives a large bonus to the player.
> I am a vampire.
>> The player believes in the Family of Arefu. They abhor killing and will instead try to stave off the psychosis as long as possible using blood packs.
- Similar to 'I am a monster.', however:
- Blood packs push the psychosis back instead of just holding it off, allowing them to be used as a permanent, if expensive, solution.
- Killing humans gives a large Karma penalty and brings the psychosis much closer, causing a 'slippery slope' situation where a player failing to keep up with the blood packs quickly degenerates into psychosis and will remain close to it until they can pull themselves away.
Comments, improvements or even a solution to detecting player kills would be much appreciated.