feat: add companion system with quest-time reduction server validation

Introduces 10 unlockable companions (Lyra, Finn, Wren, Aldric, Sera, Kael,
Zuri, Mira, Vex, Pria), each providing a unique bonus: passive gold, click
gold, boss damage, essence income, or quest-time reduction.

Quest-time reduction is validated server-side: computeQuestRewards applies
the active companion's reduction to the effective duration check, and the
income validation budget accounts for passive gold and essence bonuses.
Server recomputes unlockedCompanionIds on every save using DB-authoritative
lifetime stats and validates the active companion ID.

Companion bonuses are also applied in the client tick engine and
boss.ts calculatePartyStats.

apps/api/src/data/initialState.ts

@@ -69,4 +69,5 @@ export const INITIAL_GAME_STATE = (player: Player, characterName: string): GameS
   transcendence: { ...INITIAL_TRANSCENDENCE },
   apotheosis: { ...INITIAL_APOTHEOSIS },
   exploration: structuredClone(INITIAL_EXPLORATION),
+  companions: { unlockedCompanionIds: [], activeCompanionId: null },
 });

apps/api/src/routes/boss.ts

@@ -1,5 +1,5 @@
 import type { BossChallengeResponse, GameState } from "@elysium/types";
-import { computeSetBonuses } from "@elysium/types";
+import { computeSetBonuses, getActiveCompanionBonus } from "@elysium/types";
 import { Hono } from "hono";
 import type { HonoEnv } from "../types/hono.js";
 import { prisma } from "../db/client.js";
@@ -61,7 +61,14 @@ const calculatePartyStats = (
 
   const echoCombatMultiplier = state.transcendence?.echoCombatMultiplier ?? 1;
   const craftedCombatMultiplier = state.exploration?.craftedCombatMultiplier ?? 1;
-  partyDPS *= equipmentCombatMultiplier * setCombatMultiplier * echoCombatMultiplier * craftedCombatMultiplier;
+
+  const companionBonus = getActiveCompanionBonus(
+    state.companions?.activeCompanionId,
+    state.companions?.unlockedCompanionIds ?? [],
+  );
+  const companionCombatMult = companionBonus?.type === "bossDamage" ? 1 + companionBonus.value : 1;
+
+  partyDPS *= equipmentCombatMultiplier * setCombatMultiplier * echoCombatMultiplier * craftedCombatMultiplier * companionCombatMult;
 
   return { partyDPS, partyMaxHp };
 };

apps/api/src/routes/game.ts

@@ -1,5 +1,5 @@
 import type { GameState, LoginBonusResult, SaveRequest } from "@elysium/types";
-import { computeSetBonuses } from "@elysium/types";
+import { computeSetBonuses, computeUnlockedCompanionIds, getActiveCompanionBonus } from "@elysium/types";
 import { createHmac } from "node:crypto";
 import { Hono } from "hono";
 import type { HonoEnv } from "../types/hono.js";
@@ -58,6 +58,13 @@ const computeMaxPassiveIncome = (
   const craftedGoldMultiplier = state.exploration?.craftedGoldMultiplier ?? 1;
   const craftedEssenceMultiplier = state.exploration?.craftedEssenceMultiplier ?? 1;
 
+  const companionBonus = getActiveCompanionBonus(
+    state.companions?.activeCompanionId,
+    state.companions?.unlockedCompanionIds ?? [],
+  );
+  const companionGoldMult = companionBonus?.type === "passiveGold" ? 1 + companionBonus.value : 1;
+  const companionEssenceMult = companionBonus?.type === "essenceIncome" ? 1 + companionBonus.value : 1;
+
   let goldPerSecond = 0;
   let essencePerSecond = 0;
 
@@ -94,7 +101,7 @@ const computeMaxPassiveIncome = (
       craftedEssenceMultiplier;
   }
 
-  return { goldPerSecond, essencePerSecond };
+  return { goldPerSecond: goldPerSecond * companionGoldMult, essencePerSecond: essencePerSecond * companionEssenceMult };
 };
 
 /**
@@ -115,13 +122,20 @@ const computeMaxClickGoldPerSecond = (state: GameState): number => {
 
   const runestonesClick = state.prestige.runestonesClickMultiplier ?? 1;
 
+  const companionBonus = getActiveCompanionBonus(
+    state.companions?.activeCompanionId,
+    state.companions?.unlockedCompanionIds ?? [],
+  );
+  const companionClickMult = companionBonus?.type === "clickGold" ? 1 + companionBonus.value : 1;
+
   const clickPower =
     state.baseClickPower *
     clickMultiplier *
     state.prestige.productionMultiplier *
     runestonesClick *
     equipmentClickMultiplier *
-    setClickMultiplier;
+    setClickMultiplier *
+    companionClickMult;
 
   return clickPower * CLICK_BUFFER_CPS;
 };
@@ -134,12 +148,14 @@ const computeMaxClickGoldPerSecond = (state: GameState): number => {
  *  - It is now "completed" in the incoming state.
  *
  * Reward amounts and durations are taken from DEFAULT_QUESTS (authoritative game data)
- * to prevent client-side reward or duration tampering.
+ * to prevent client-side reward or duration tampering. The questTimeReduction parameter
+ * (0–1 fraction) applies a companion time bonus to the effective duration check.
  */
 const computeQuestRewards = (
   incoming: GameState,
   previous: GameState,
   now: number,
+  questTimeReduction: number,
 ): { gold: number; essence: number } => {
   let gold = 0;
   let essence = 0;
@@ -157,7 +173,9 @@ const computeQuestRewards = (
     const questData = DEFAULT_QUESTS.find((q) => q.id === incomingQuest.id);
     if (!questData) continue;
 
-    if (prevQuest.startedAt + questData.durationSeconds * 1000 > now + QUEST_GRACE_MS) continue;
+    // Apply companion quest-time reduction to the effective duration check.
+    const effectiveDuration = questData.durationSeconds * (1 - questTimeReduction);
+    if (prevQuest.startedAt + effectiveDuration * 1000 > now + QUEST_GRACE_MS) continue;
 
     for (const reward of questData.rewards) {
       if (reward.type === "gold" && reward.amount != null) gold += reward.amount;
@@ -230,8 +248,15 @@ const validateAndSanitize = (incoming: GameState, previous: GameState): GameStat
   const { goldPerSecond, essencePerSecond } = computeMaxPassiveIncome(previous);
   const clickGoldPerSecond = computeMaxClickGoldPerSecond(previous);
 
+  // Determine quest-time reduction from the companion active in the previous (trusted) state.
+  const prevCompanionBonus = getActiveCompanionBonus(
+    previous.companions?.activeCompanionId,
+    previous.companions?.unlockedCompanionIds ?? [],
+  );
+  const questTimeReduction = prevCompanionBonus?.type === "questTime" ? prevCompanionBonus.value : 0;
+
   // Precise one-time rewards for events that could have occurred this interval.
-  const questRewards = computeQuestRewards(incoming, previous, now);
+  const questRewards = computeQuestRewards(incoming, previous, now, questTimeReduction);
   const bossRewards = computeBossRewards(incoming, previous);
 
   // Passive and click income receive a 2× buffer to cover mid-session adventurer/upgrade
@@ -775,6 +800,29 @@ gameRouter.post("/save", async (context) => {
     player: { ...stateToSave.player, lastSavedAt: now },
   };
 
+  // Recompute companion unlocks server-side using DB-authoritative player lifetime stats.
+  // This prevents clients from claiming companions they haven't legitimately unlocked.
+  const companionUnlocks = computeUnlockedCompanionIds({
+    lifetimeBossesDefeated: playerRecord?.lifetimeBossesDefeated ?? 0,
+    lifetimeQuestsCompleted: playerRecord?.lifetimeQuestsCompleted ?? 0,
+    lifetimeGoldEarned: playerRecord?.lifetimeGoldEarned ?? 0,
+    prestigeCount: stateToSave.prestige.count,
+    transcendenceCount: stateToSave.transcendence?.count ?? 0,
+    apotheosisCount: stateToSave.apotheosis?.count ?? 0,
+  });
+  const clientActiveCompanionId = stateToSave.companions?.activeCompanionId ?? null;
+  const validatedActiveCompanionId =
+    clientActiveCompanionId !== null && companionUnlocks.includes(clientActiveCompanionId)
+      ? clientActiveCompanionId
+      : null;
+  stateToSave = {
+    ...stateToSave,
+    companions: {
+      unlockedCompanionIds: companionUnlocks,
+      activeCompanionId: validatedActiveCompanionId,
+    },
+  };
+
   const currentUnlocked = parseUnlockedTitles(playerRecord?.unlockedTitles);
   const newTitles = checkAndUnlockTitles(
     currentUnlocked,

apps/web/src/components/game/AboutPanel.tsx

@@ -87,6 +87,10 @@ const HOW_TO_PLAY = [
     title: "🤖 Auto-Quest & Auto-Boss",
     body: "Toggle automation in the Quests and Boss Encounters panels! Auto-Quest automatically sends your party on the highest-zone available quest as soon as one completes, skipping quests whose combat power requirement isn't met. Auto-Boss automatically challenges the highest available boss as soon as one is ready. Both can be toggled on or off at any time using the 🤖 Auto button in each panel header.",
   },
+  {
+    title: "👥 Companions",
+    body: "Unlock companions by reaching certain milestones across all your runs. Each companion provides a powerful permanent bonus: increased passive gold, click gold, boss damage, essence income, or reduced quest time. You can only have one companion active at a time — choose wisely based on your current strategy! Companions are unlocked permanently once their condition is met and will never be lost.",
+  },
   {
     title: "☁️ Cloud Saves",
     body: "Your progress is automatically saved to the cloud every 30 seconds whilst you play. You can also force a manual save at any time using the sync button in the resource bar. Your save is protected by HMAC validation to ensure data integrity.",

apps/web/src/components/game/CompanionPanel.tsx

@@ -0,0 +1,117 @@
+import { COMPANIONS } from "@elysium/types";
+import type { Companion } from "@elysium/types";
+import { useGame } from "../../context/GameContext.js";
+
+const BONUS_LABELS: Record<string, string> = {
+  passiveGold: "Passive Gold",
+  clickGold: "Click Gold",
+  bossDamage: "Boss Damage",
+  essenceIncome: "Essence Income",
+  questTime: "Quest Time",
+};
+
+const UNLOCK_LABELS: Record<string, string> = {
+  lifetimeBosses: "lifetime bosses defeated",
+  lifetimeQuests: "lifetime quests completed",
+  lifetimeGold: "lifetime gold earned",
+  prestige: "prestige(s)",
+  transcendence: "transcendence(s)",
+  apotheosis: "apotheosis",
+};
+
+const formatThreshold = (type: string, threshold: number): string => {
+  if (type === "lifetimeGold") {
+    if (threshold >= 1e12) return `${(threshold / 1e12).toFixed(0)}T`;
+    if (threshold >= 1e9) return `${(threshold / 1e9).toFixed(0)}B`;
+    if (threshold >= 1e6) return `${(threshold / 1e6).toFixed(0)}M`;
+    if (threshold >= 1e3) return `${(threshold / 1e3).toFixed(0)}K`;
+    return threshold.toString();
+  }
+  return threshold.toString();
+};
+
+const CompanionCard = ({
+  companion,
+  isUnlocked,
+  isActive,
+  onSelect,
+}: {
+  companion: Companion;
+  isUnlocked: boolean;
+  isActive: boolean;
+  onSelect: () => void;
+}): React.JSX.Element => {
+  const bonusSign = companion.bonus.type === "questTime" ? "-" : "+";
+  const bonusPercent = Math.round(companion.bonus.value * 100);
+  const bonusLabel = BONUS_LABELS[companion.bonus.type] ?? companion.bonus.type;
+
+  return (
+    <div className={`companion-card ${isUnlocked ? "companion-unlocked" : "companion-locked"} ${isActive ? "companion-active" : ""}`}>
+      <div className="companion-header">
+        <div className="companion-name-block">
+          <span className="companion-name">{companion.name}</span>
+          <span className="companion-title">{companion.title}</span>
+        </div>
+        {isActive && <span className="companion-active-badge">Active</span>}
+      </div>
+
+      <p className="companion-description">{companion.description}</p>
+
+      <div className="companion-bonus">
+        <span className="companion-bonus-label">{bonusLabel}</span>
+        <span className="companion-bonus-value">{bonusSign}{bonusPercent}%</span>
+      </div>
+
+      {isUnlocked ? (
+        <button
+          className={`companion-select-btn ${isActive ? "companion-select-active" : ""}`}
+          onClick={onSelect}
+          type="button"
+        >
+          {isActive ? "Deactivate" : "Activate"}
+        </button>
+      ) : (
+        <div className="companion-unlock-requirement">
+          🔒 Unlock: {formatThreshold(companion.unlock.type, companion.unlock.threshold)} {UNLOCK_LABELS[companion.unlock.type] ?? companion.unlock.type}
+        </div>
+      )}
+    </div>
+  );
+};
+
+export const CompanionPanel = (): React.JSX.Element => {
+  const { state, setActiveCompanion } = useGame();
+
+  if (!state) return <></>;
+
+  const unlockedIds = state.companions?.unlockedCompanionIds ?? [];
+  const activeId = state.companions?.activeCompanionId ?? null;
+
+  const handleSelect = (companionId: string): void => {
+    setActiveCompanion(activeId === companionId ? null : companionId);
+  };
+
+  return (
+    <div className="companion-panel">
+      <h2>👥 Companions</h2>
+      <p className="companion-intro">
+        Companions provide powerful bonuses while active. You can only have one companion active at a time.
+        {activeId && (
+          <> Currently active: <strong>{COMPANIONS.find((c) => c.id === activeId)?.name ?? activeId}</strong>.</>
+        )}
+      </p>
+
+      <div className="companion-grid">
+        {COMPANIONS.map((companion) => (
+          <CompanionCard
+            key={companion.id}
+            companion={companion}
+            isUnlocked={unlockedIds.includes(companion.id)}
+            isActive={activeId === companion.id}
+            onSelect={() => { handleSelect(companion.id); }}
+          />
+        ))}
+      </div>
+    </div>
+  );
+};

apps/web/src/components/game/GameLayout.tsx

@@ -22,10 +22,11 @@ import { UpgradePanel } from "./UpgradePanel.js";
 import { DailyChallengePanel } from "./DailyChallengePanel.js";
 import { ExplorationPanel } from "./ExplorationPanel.js";
 import { CharacterSheetPanel } from "./CharacterSheetPanel.js";
+import { CompanionPanel } from "./CompanionPanel.js";
 import { CraftingPanel } from "./CraftingPanel.js";
 import { LoginBonusModal } from "./LoginBonusModal.js";
 
-type Tab = "adventurers" | "upgrades" | "quests" | "bosses" | "equipment" | "achievements" | "prestige" | "transcendence" | "apotheosis" | "statistics" | "daily" | "codex" | "about" | "exploration" | "crafting" | "character";
+type Tab = "adventurers" | "upgrades" | "quests" | "bosses" | "equipment" | "achievements" | "prestige" | "transcendence" | "apotheosis" | "statistics" | "daily" | "codex" | "about" | "exploration" | "crafting" | "character" | "companions";
 
 const BASE_TABS: { id: Tab; label: string }[] = [
   { id: "adventurers", label: "⚔️ Adventurers" },
@@ -40,6 +41,7 @@ const BASE_TABS: { id: Tab; label: string }[] = [
   { id: "transcendence", label: "🌌 Transcendence" },
   { id: "apotheosis", label: "✨ Apotheosis" },
   { id: "statistics", label: "📊 Statistics" },
+  { id: "companions", label: "👥 Companions" },
   { id: "character", label: "📋 Character" },
   { id: "achievements", label: "🏆 Achievements" },
   { id: "codex", label: "📖 Codex" },
@@ -135,6 +137,7 @@ export const GameLayout = (): React.JSX.Element => {
             {activeTab === "crafting" && <CraftingPanel />}
             {activeTab === "statistics" && <StatisticsPanel />}
             {activeTab === "daily" && <DailyChallengePanel />}
+            {activeTab === "companions" && <CompanionPanel />}
             {activeTab === "character" && <CharacterSheetPanel />}
             {activeTab === "codex" && <CodexPanel />}
             {activeTab === "about" && <AboutPanel />}

apps/web/src/context/GameContext.tsx

@@ -208,6 +208,8 @@ interface GameContextValue {
   loginStreak: number;
   /** Dismiss the login bonus modal */
   dismissLoginBonus: () => void;
+  /** Set the active companion (null to deactivate) */
+  setActiveCompanion: (companionId: string | null) => void;
 }
 
 const GameContext = createContext<GameContextValue | null>(null);
@@ -909,6 +911,21 @@ export const GameProvider = ({ children }: { children: React.ReactNode }): React
     });
   }, []);
 
+  const setActiveCompanion = useCallback((companionId: string | null) => {
+    setState((prev) => {
+      if (!prev) return prev;
+      const unlockedIds = prev.companions?.unlockedCompanionIds ?? [];
+      const validatedId = companionId !== null && unlockedIds.includes(companionId) ? companionId : null;
+      return {
+        ...prev,
+        companions: {
+          unlockedCompanionIds: unlockedIds,
+          activeCompanionId: validatedId,
+        },
+      };
+    });
+  }, []);
+
   const challengeBoss = useCallback(async (bossId: string) => {
     if (!stateRef.current) return;
     const boss = stateRef.current.bosses.find((b) => b.id === bossId);
@@ -995,6 +1012,7 @@ export const GameProvider = ({ children }: { children: React.ReactNode }): React
         loginBonus,
         loginStreak,
         dismissLoginBonus,
+        setActiveCompanion,
       }}
     >
       {children}

apps/web/src/engine/tick.ts

@@ -1,5 +1,5 @@
 import type { Achievement, Equipment, GameState } from "@elysium/types";
-import { computeSetBonuses } from "@elysium/types";
+import { computeSetBonuses, getActiveCompanionBonus } from "@elysium/types";
 import { EQUIPMENT_SETS } from "../data/equipmentSets.js";
 import { updateChallengeProgress } from "../utils/dailyChallenges.js";
 
@@ -94,6 +94,14 @@ export const applyTick = (state: GameState, deltaSeconds: number): GameState =>
   const craftedGoldMultiplier = state.exploration?.craftedGoldMultiplier ?? 1;
   const craftedEssenceMultiplier = state.exploration?.craftedEssenceMultiplier ?? 1;
 
+  const companionBonus = getActiveCompanionBonus(
+    state.companions?.activeCompanionId,
+    state.companions?.unlockedCompanionIds ?? [],
+  );
+  const companionGoldMult = companionBonus?.type === "passiveGold" ? 1 + companionBonus.value : 1;
+  const companionEssenceMult = companionBonus?.type === "essenceIncome" ? 1 + companionBonus.value : 1;
+  const companionQuestTimeReduction = companionBonus?.type === "questTime" ? companionBonus.value : 0;
+
   let goldGained = 0;
   let essenceGained = 0;
 
@@ -123,6 +131,7 @@ export const applyTick = (state: GameState, deltaSeconds: number): GameState =>
       equipmentGoldMultiplier *
       setGoldMultiplier *
       craftedGoldMultiplier *
+      companionGoldMult *
       deltaSeconds;
 
     essenceGained +=
@@ -132,6 +141,7 @@ export const applyTick = (state: GameState, deltaSeconds: number): GameState =>
       prestige *
       runestonesEssence *
       craftedEssenceMultiplier *
+      companionEssenceMult *
       deltaSeconds;
   }
 
@@ -146,10 +156,11 @@ export const applyTick = (state: GameState, deltaSeconds: number): GameState =>
   let updatedEquipment = state.equipment ?? [];
 
   const updatedQuests = state.quests.map((quest) => {
+    const effectiveQuestMs = quest.durationSeconds * (1 - companionQuestTimeReduction) * 1000;
     if (
       quest.status !== "active" ||
       quest.startedAt == null ||
-      now < quest.startedAt + quest.durationSeconds * 1000
+      now < quest.startedAt + effectiveQuestMs
     ) {
       return quest;
     }
@@ -323,6 +334,12 @@ export const calculateClickPower = (state: GameState): number => {
   const echoIncome = state.transcendence?.echoIncomeMultiplier ?? 1;
   const craftedClickMultiplier = state.exploration?.craftedClickMultiplier ?? 1;
 
+  const companionClickBonus = getActiveCompanionBonus(
+    state.companions?.activeCompanionId,
+    state.companions?.unlockedCompanionIds ?? [],
+  );
+  const companionClickMult = companionClickBonus?.type === "clickGold" ? 1 + companionClickBonus.value : 1;
+
   return (
     state.baseClickPower *
     clickMultiplier *
@@ -331,6 +348,7 @@ export const calculateClickPower = (state: GameState): number => {
     echoIncome *
     equipmentClickMultiplier *
     setClickMultiplier *
-    craftedClickMultiplier
+    craftedClickMultiplier *
+    companionClickMult
   );
 };

apps/web/src/styles.css

@@ -3966,3 +3966,139 @@ body {
   font-size: 0.95rem;
   font-weight: 600;
 }
+
+/* ── Companions ──────────────────────────────────────────────────────── */
+
+.companion-panel h2 {
+  margin-bottom: 0.5rem;
+}
+
+.companion-intro {
+  font-size: 0.9rem;
+  color: var(--colour-muted);
+  margin-bottom: 1.25rem;
+}
+
+.companion-intro strong {
+  color: var(--colour-accent);
+}
+
+.companion-grid {
+  display: grid;
+  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
+  gap: 1rem;
+}
+
+.companion-card {
+  background: var(--colour-surface);
+  border: 1px solid var(--colour-border);
+  border-radius: 8px;
+  padding: 1rem;
+  display: flex;
+  flex-direction: column;
+  gap: 0.6rem;
+  transition: border-color 0.2s;
+}
+
+.companion-unlocked {
+  border-color: var(--colour-border);
+}
+
+.companion-locked {
+  opacity: 0.6;
+}
+
+.companion-active {
+  border-color: var(--colour-accent);
+  box-shadow: 0 0 0 1px var(--colour-accent);
+}
+
+.companion-header {
+  display: flex;
+  align-items: flex-start;
+  justify-content: space-between;
+  gap: 0.5rem;
+}
+
+.companion-name-block {
+  display: flex;
+  flex-direction: column;
+  gap: 0.15rem;
+}
+
+.companion-name {
+  font-weight: 700;
+  font-size: 1rem;
+  color: var(--colour-text);
+}
+
+.companion-title {
+  font-size: 0.78rem;
+  color: var(--colour-muted);
+  font-style: italic;
+}
+
+.companion-active-badge {
+  background: var(--colour-accent);
+  color: #fff;
+  font-size: 0.72rem;
+  font-weight: 700;
+  padding: 0.15rem 0.5rem;
+  border-radius: 999px;
+  white-space: nowrap;
+}
+
+.companion-description {
+  font-size: 0.85rem;
+  color: var(--colour-muted);
+  line-height: 1.4;
+  flex: 1;
+}
+
+.companion-bonus {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  background: rgba(120, 80, 200, 0.12);
+  border-radius: 6px;
+  padding: 0.35rem 0.6rem;
+}
+
+.companion-bonus-label {
+  font-size: 0.82rem;
+  color: var(--colour-muted);
+}
+
+.companion-bonus-value {
+  font-size: 0.9rem;
+  font-weight: 700;
+  color: var(--colour-accent);
+}
+
+.companion-select-btn {
+  padding: 0.45rem 0.8rem;
+  border-radius: 6px;
+  border: 1px solid var(--colour-accent);
+  background: transparent;
+  color: var(--colour-accent);
+  font-size: 0.85rem;
+  font-weight: 600;
+  cursor: pointer;
+  transition: background 0.15s, color 0.15s;
+}
+
+.companion-select-btn:hover {
+  background: var(--colour-accent);
+  color: #fff;
+}
+
+.companion-select-active {
+  background: var(--colour-accent);
+  color: #fff;
+}
+
+.companion-unlock-requirement {
+  font-size: 0.8rem;
+  color: var(--colour-muted);
+  padding: 0.35rem 0;
+}