When we reuse institutions (theater companies, galleries, clinics, courts) across multiple King in Yellow scenarios, what specific prep techniques let NPCs and locations accumulate visible ‘Carcosa scars’—changed policies, décor, diagnostic categories, inside jokes—so that returning to them becomes an investigative tool for tracing contagion and not just a backdrop continuity detail?

Answer

Use light, trackable "scar" prep so each return visit shows visible change tied to Carcosa, and make those changes mechanically searchable.

1. Scar tracks per institution

• For each recurring institution, prep a 0–3 track in 3–4 fronts (e.g. Contagion, Identity, Reputation, Procedures).
• When scenarios end, tick 1–2 fronts based on what happened there.
• At next prep, give each tick one small, specific change.

2. Scar tables (prep once, reuse) For each front, write a 6–item table of low-key scars:

• Contagion: new symbol in logo; security sign with Yellow Sign-like pictogram; staff in-joke about "going to Carcosa".
• Identity: staff renamed roles ("curators" → "conductors"); masks allowed/required; new dress or patient category.
• Reputation: new slogan; rumor; press clipping on wall.
• Procedures: changed intake forms; new policy posted; odd checklist item. Roll or pick 1–2 per advance.

3. Scar snapshots for locations and NPCs

• For each recurring site, keep a 3-line "snapshot": décor, policy, mood.
• Each return, revise one line using the scar tables.
• For 2–3 key NPCs, keep a similar 3-line sheet: role, demeanor, visible belief about Carcosa.
• On a scar, tweak one line only (keeps them recognizable but changed).

4. Make scars investigable

• Tie 1–2 clues per visit directly to scars: changed file labels, artwork, diagnostic codes, in-joke phrases.
• Simple move: when a PC asks, "What’s different since last time?", give 1 concrete scar + 1 inference about how the last scenario echoed here.
• Let players cross-compare scars across institutions (e.g. same new category name appears in clinic and court).

5. Session-to-session procedure After each scenario:

• For each institution touched, answer 2 prompts:
  1. "What got more Carcosa?" (tick a front, add 1 scar.)
  2. "What pushed back?" (optional stabilizing change: extra security, counter-symbolism.)
• Note 2–3 words per change; elaborate only on return.

6. Safety layer

• Before play, agree lines/veils on real-world diagnoses, courts, and clinics.
• Phrase scars abstractly when needed ("new risk code" instead of a real-world label) and invite player veto on any scar that hits too close.

Net effect: institutions accumulate small, legible changes driven by prior play. Returning to them feels like reading a living casefile on Carcosa’s spread, not just enjoying continuity.