diff --git a/guide/age-of-four/src/data/engine.ts b/guide/age-of-four/src/data/engine.ts
index 8f0f9282..7e5f9dd7 100644
--- a/guide/age-of-four/src/data/engine.ts
+++ b/guide/age-of-four/src/data/engine.ts
@@ -85,20 +85,6 @@ export const weatherEvents: MergedWeatherEvent[] = []
 export const leyChanneling: LeyChanneling =
   (climateSpecFile as Record<string, unknown>).ley_channeling as LeyChanneling
 
-// ─── Corruption Terrain Modifiers ───────────────────────────────────────────
-
-export interface CorruptionTerrainEntry { id: string; name: string; modifier: number }
-
-export const corruptionTerrainModifiers: CorruptionTerrainEntry[] = allTerrains
-  .filter((t) => t.terrain_power?.corruption_spread_modifier != null
-    && t.terrain_power.corruption_spread_modifier !== 1.0)
-  .map((t) => ({
-    id: t.id,
-    name: t.name,
-    modifier: t.terrain_power.corruption_spread_modifier!,
-  }))
-  .sort((a, b) => b.modifier - a.modifier)
-
 // ─── Climate Scalar Constants ────────────────────────────────────────────────
 // These come from climate_params.json (M2); use built-in defaults for M0/M1.
 
diff --git a/guide/age-of-four/src/data/index.ts b/guide/age-of-four/src/data/index.ts
index f0b4d9e7..e9bac733 100644
--- a/guide/age-of-four/src/data/index.ts
+++ b/guide/age-of-four/src/data/index.ts
@@ -14,8 +14,6 @@ export {
   type MergedWeatherEvent,
   weatherEvents,
   leyChanneling,
-  type CorruptionTerrainEntry,
-  corruptionTerrainModifiers,
   qualityUpThreshold,
   qualityDownThreshold,
   mountainRainShadowBlock,