Take the "insanity" rules from "sundown slashers" an place them in the main rules.
Write the entire Sundown Slashers Scenario into the main rules
RENAME: Zombies -> Minions!
Investigate an investigation counter by rolling 1 six sided die and compare the result rolled to this table:
1: Ambush -> Raise this model's Insanity by 1. Place the Slasher at full health in base to base contact to the investigating model. The model's turn ends and the Slasher acts immediately.
2: Trap -> Raise this model's Insanity by 1. Place 1D6 Minions in base to base contact to the investigating model. The model's turn ends and one of those Minions acts immediately.
3: Scare -> Raise this model's Insanity by 1. This model immediately moves its full movement towards the corner it started in. This is an additional movement. This time, only if this additional movment ends in base to base contact to an opposing model, a Duel is initiated.
4: Hint -> This model may immediately move its full movement towards the next Investigation marker. This is an additional movement. This time, only if this additional movment ends in base to base contact to an opposing model, a Duel is initiated.
5: Clue -> This model receives a clue marker. Discard the clue marker any time whenever this model gets to roll dice, to roll 1 additional die.
6: Fact -> This model recieves a fact marker. Discard the fact marker any time whenever this model gets to roll dice to add 1 to each die rolled. You can apply this modifier only once.
7: Secret -> Remove the Jumpscare Marker the closest to this model
What's following is a brainstorm - I hope anything of this makes sense, when I re-write this into the rulebook:
Strange cults following ancient deities with unspeakable names battle each other.
Heroes can purchase the scenario specific traits "Occultist" and "Choir" (see below).
For this scenario, a player's warband is called a Cult.
Each Cult is in possession of a Book of Rituals. Inside this book all the Rituals known to a Cult can be found. Each Hero with the trait "Occultist" is able to perform any one of the Rituals from his Cult's Book of Rituals during his activation.
Each cult starts with a Spirit Die on 1. Each cult uses a separate Spirit die and each cult's Spirit die is used for the entire cult.
Only Heroes can perform Rituals. Each ritual uses up one action. After performing a ritual, a Hero rolls his 3 dice, adding the value of the Spirit Die to each of them. Each result of 7 or more leads to 1 "Incantation", but also raises the performing Hero's insanity by 1. Then the Spirit Die is raised by 1.
If a Hero starts performing a Ritual within line of sight to any number of opposing fighters, he immediately initiates a Duel using the value of his cult's Spirit Die as his Duel Score. The opposing fighters return fire as usual. If the initiating Hero gets to act first or at the same time as one of the other fighters, he can roll for Incantations unhindered. If any other fighter gets to return fire before the initiating Hero and scores at least 1 hit, additionally to damage the Ritual is interrupted and does not get resolved. In that case the cult's Spirit Die is not raised either.
A Hero may buy the Trait "Choir". "Choir" can be bought once per ganger the Hero has bought as follower. "Choir" allows a Hero to ignore the first X levels of insanity with X being the number of times "Choir" has been bought.
A Hero can perform an action to "soothe the spirits" - to reduce the Spirit Die by 1. The Spirit Die can never be reduced below 1.
A Hero may buy the Trait "Occultist". For each time this trait has been bought, the Hero adds 1 Ritual to the Book of Rituals known to the Cult. Each Hero with at least one "Occultist" Trait may use his cult's entire Book of Rituals to perform a Ritual (see above) at any time during a Match.
A ritual always requires a target other than the Hero performing it. The term "this fighter" in a ritual's description thus always means the fighter targeted by the ritual. X always is the number of "Incantations" of a ritual. You might want to use counters to show, which ritual has been cast at which strength onto a fighter. A fighter can only be affected by the effects of one Ritual at any given time. As long as a ritual is active on a fighter, that fighter cannot become the target of a Ritual other than Neutralize.
The next time this fighter initiates or becomes engaged in a Duel, a fighter rolling dice against this fighter does so with a modifier of -X.
The next time this fighter initiates a Duel in melee, he does so with an additional X dice.
Initiate a Duel with an opposing fighter in melee. If the opposing fighter is removed from play, this fighter immediately recovers X Toughness up to his initial value in Toughness.
For the next X rounds, whenever this fighter becomes engaged in a duel and survives, he may immediately initiate a Duel in return. This does not count against this fighter's regular actions.
This fighter as well as each model at least partially within X" to this fighter immediately suffers 1 hit.
This fighter cannot perform his next action. As long as this fighter does not move (voluntarily or involuntarily), each other fighter within X inches to this fighter ignores 1 hit during each Duel.
Immediately move this fighter X inches into any one direction. This does not cause this fighter to initiate a Duel.
This fighter has to reroll up to the next X hits he scores during his next Duel.
If this fighter ends his next Action within 2X" to one of his allied models, he initiates a Duel with that model if possible. You then get to select the duel score and to roll the dice for this fighter.
When performing a ritual during his next activation, this fighter has to reroll up to X Incantations and take the 2nd result instead.
If this opposing fighter is within X" to the performer of this Ritual, immediately perform an activation with this fighter. This activation does not count as this fighter's regular activation.
During his next activation, when moving this fighter may ignore one obstacle up to X" high and X" deep. This fighter has to end his movement in a valid position, though.
Until his next activation, other models not in base to base contact to this fighter cannot initiate a Duel with this fighter for as long as this fighter does not return fire on an opposing model ending its activation within line of sight to this fighter. If during his next activation this fighter moves no more than X", the effect remains in place until the end of the round.
Remove the effect of a ritual on this fighter, if this fighter is within 8X" of the performer of this Ritual.
If this allied fighter is within 4X" to the performer of this Ritual, perform an activation with this fighter. This does not count as this fighter's regular activation.
All models within X" to this fighter are immediately placed prone. Any Hero among them becomes stunned.
All models within 2X" to this fighter immediately perform one movement action in a straight line away from this fighter. This does not count against the regular action of those models.
Summon a duplicate of this fighter, if this fighter is a ganger allied to the performer of this Ritual. The duplicate may activate from the beginning of the next roud on and it stays either until the end of the next X round(s) or upon receiving 1 hit.
This fighter may reroll up to X dice not scoring a hit the next time he is engaged in a Duel.
During his next activation, this fighter may perform X actions additionally. After each of these actions he needs to check, whether he initiates a Duel.
If this fighter does not perform any action during his next activation, he receives a modifier of +X whenever he returns fire until his next activation.
During his next activation, whenever this fighter targets another model with an action, he receives a -X modifier on any die he rolls.
This fighter as well as all other models within X" that are either prone or stunned are immediately stood up. If they haven't acted yet this turn, they may act from their player's next turn on.
This fighter immediately receives X hits.