diff --git a/PROGRESS.md b/PROGRESS.md
index 78018cc..dd4fd9e 100644
--- a/PROGRESS.md
+++ b/PROGRESS.md
@@ -455,7 +455,7 @@
   - Frontend fetches from R2 (`https://r2.aicodebattle.com/evolution/live.json`)
   - Cache-Control: max-age=10 for near-real-time updates
   - Tests for R2 config validation and credential handling
-- [ ] Narrative engine (weekly story arc detection + LLM chronicles)
+- [x] Narrative engine (weekly story arc detection + LLM chronicles)
 - [x] Public match data documentation (OpenAPI-style)
   - New `/docs/api` route with comprehensive endpoint documentation
   - Documents Pages, R2, and B2 static JSON endpoints
diff --git a/cmd/acb-index-builder/config.go b/cmd/acb-index-builder/config.go
index 1715790..53997f8 100644
--- a/cmd/acb-index-builder/config.go
+++ b/cmd/acb-index-builder/config.go
@@ -75,6 +75,9 @@ func LoadConfig() *Config {
 		B2BucketName: os.Getenv("ACB_B2_BUCKET"),
 
 		OutputDir: getEnv("ACB_OUTPUT_DIR", "/tmp/acb-index"),
+
+		LLMBaseURL: getEnv("ACB_LLM_BASE_URL", ""),
+		LLMAPIKey:  os.Getenv("ACB_LLM_API_KEY"),
 	}
 }
 
diff --git a/cmd/acb-index-builder/main.go b/cmd/acb-index-builder/main.go
index b3016ec..8dd2720 100644
--- a/cmd/acb-index-builder/main.go
+++ b/cmd/acb-index-builder/main.go
@@ -147,7 +147,11 @@ func runBuildCycle(ctx context.Context, db *sql.DB, cfg *Config) error {
 	}
 
 	// Generate blog posts (weekly meta reports and chronicles)
-	if err := generateBlog(data, cfg.OutputDir); err != nil {
+	var llmClient *LLMClient
+	if cfg.LLMBaseURL != "" {
+		llmClient = NewLLMClient(cfg.LLMBaseURL, cfg.LLMAPIKey)
+	}
+	if err := generateBlog(data, cfg.OutputDir, llmClient); err != nil {
 		slog.Error("Failed to generate blog", "error", err)
 		// Non-fatal - continue with rest of build
 	}
diff --git a/cmd/acb-index-builder/main_test.go b/cmd/acb-index-builder/main_test.go
index b1914db..3bd2b8c 100644
--- a/cmd/acb-index-builder/main_test.go
+++ b/cmd/acb-index-builder/main_test.go
@@ -191,7 +191,7 @@ func TestGenerateMatchIndex(t *testing.T) {
 				TurnCount:    200,
 				EndCondition: "elimination",
 				CompletedAt:  now,
-				Participants: []MatchParticipant{
+				Participants: []ParticipantData{
 					{BotID: "bot1", Score: 5, Won: true},
 					{BotID: "bot2", Score: 2, Won: false},
 				},
@@ -246,7 +246,7 @@ func TestGeneratePlaylists(t *testing.T) {
 				TurnCount:    200,
 				EndCondition: "elimination",
 				CompletedAt:  now,
-				Participants: []MatchParticipant{
+				Participants: []ParticipantData{
 					{BotID: "bot1", Score: 3, Won: true},
 					{BotID: "bot2", Score: 2, Won: false}, // Close finish (diff = 1)
 				},
@@ -257,7 +257,7 @@ func TestGeneratePlaylists(t *testing.T) {
 				TurnCount:    150,
 				EndCondition: "dominance",
 				CompletedAt:  now.Add(-time.Hour),
-				Participants: []MatchParticipant{
+				Participants: []ParticipantData{
 					{BotID: "bot1", Score: 0, Won: false},
 					{BotID: "bot2", Score: 10, Won: true}, // Not close (diff = 10)
 				},
diff --git a/cmd/acb-index-builder/narrative.go b/cmd/acb-index-builder/narrative.go
index cfbaf35..0233323 100644
--- a/cmd/acb-index-builder/narrative.go
+++ b/cmd/acb-index-builder/narrative.go
@@ -41,6 +41,11 @@ type StoryArc struct {
 	ParentIDs    []string   `json:"parent_ids,omitempty"`
 	Generation   int        `json:"generation,omitempty"`
 	CommunityHint string    `json:"community_hint,omitempty"`
+
+	// Rivalry-specific fields
+	BotAWins     int `json:"bot_a_wins,omitempty"`
+	BotBWins     int `json:"bot_b_wins,omitempty"`
+	TotalMatches int `json:"total_matches,omitempty"`
 }
 
 // KeyMatch represents a key match for narrative context
@@ -430,17 +435,13 @@ func detectRivalryArcs(data *IndexData) []StoryArc {
 		}
 		botAID, botBID := parts[0], parts[1]
 
-		// Count wins for each bot and check alternation
+		// Count wins for each bot
 		botAWins := 0
 		botBWins := 0
-		alternating := true
-		lastWinner := ""
 
 		for _, m := range matches {
-			var winnerID string
 			for _, p := range m.Participants {
 				if p.Won {
-					winnerID = p.BotID
 					if p.BotID == botAID {
 						botAWins++
 					} else if p.BotID == botBID {
@@ -449,10 +450,6 @@ func detectRivalryArcs(data *IndexData) []StoryArc {
 					break
 				}
 			}
-			if lastWinner != "" && winnerID == lastWinner {
-				alternating = false
-			}
-			lastWinner = winnerID
 		}
 
 		// Only include if wins are reasonably close (not one-sided)
@@ -500,7 +497,7 @@ func detectUpsetArcs(data *IndexData) []StoryArc {
 		}
 
 		// Check if underdog won (winner had lower rating)
-		gap := loser.PreMatchRating - winner.PreMatchRating
+		gap := int(loser.PreMatchRating - winner.PreMatchRating)
 		if gap > biggestGap {
 			biggestGap = gap
 			biggestUpset = &StoryArc{