diff --git a/src/game/combat/equipmentService.ts b/src/game/combat/equipmentService.ts
new file mode 100644
index 0000000..befc584
--- /dev/null
+++ b/src/game/combat/equipmentService.ts
@@ -0,0 +1,87 @@
+import { prisma } from '../../core/database/prisma';
+import type { ItemProps } from '../economy/types';
+
+function parseItemProps(json: unknown): ItemProps {
+  if (!json || typeof json !== 'object') return {};
+  return json as ItemProps;
+}
+
+export async function ensurePlayerState(userId: string, guildId: string) {
+  return prisma.playerState.upsert({
+    where: { userId_guildId: { userId, guildId } },
+    update: {},
+    create: { userId, guildId },
+  });
+}
+
+export async function getEquipment(userId: string, guildId: string) {
+  const eq = await prisma.playerEquipment.upsert({
+    where: { userId_guildId: { userId, guildId } },
+    update: {},
+    create: { userId, guildId },
+  });
+  const weapon = eq.weaponItemId ? await prisma.economyItem.findUnique({ where: { id: eq.weaponItemId } }) : null;
+  const armor = eq.armorItemId ? await prisma.economyItem.findUnique({ where: { id: eq.armorItemId } }) : null;
+  const cape = eq.capeItemId ? await prisma.economyItem.findUnique({ where: { id: eq.capeItemId } }) : null;
+  return { eq, weapon, armor, cape } as const;
+}
+
+export async function setEquipmentSlot(userId: string, guildId: string, slot: 'weapon'|'armor'|'cape', itemId: string | null) {
+  const data = slot === 'weapon' ? { weaponItemId: itemId }
+    : slot === 'armor' ? { armorItemId: itemId }
+    : { capeItemId: itemId };
+  return prisma.playerEquipment.upsert({
+    where: { userId_guildId: { userId, guildId } },
+    update: data,
+    create: { userId, guildId, ...data },
+  });
+}
+
+export type EffectiveStats = {
+  damage: number;
+  defense: number;
+  maxHp: number;
+  hp: number;
+};
+
+async function getMutationBonuses(userId: string, guildId: string, itemId?: string | null) {
+  if (!itemId) return { damageBonus: 0, defenseBonus: 0, maxHpBonus: 0 };
+  const inv = await prisma.inventoryEntry.findUnique({ where: { userId_guildId_itemId: { userId, guildId, itemId } } });
+  if (!inv) return { damageBonus: 0, defenseBonus: 0, maxHpBonus: 0 };
+  const links = await prisma.inventoryItemMutation.findMany({ where: { inventoryId: inv.id }, include: { mutation: true } });
+  let damageBonus = 0, defenseBonus = 0, maxHpBonus = 0;
+  for (const l of links) {
+    const eff = (l.mutation.effects as any) || {};
+    if (typeof eff.damageBonus === 'number') damageBonus += eff.damageBonus;
+    if (typeof eff.defenseBonus === 'number') defenseBonus += eff.defenseBonus;
+    if (typeof eff.maxHpBonus === 'number') maxHpBonus += eff.maxHpBonus;
+  }
+  return { damageBonus, defenseBonus, maxHpBonus };
+}
+
+export async function getEffectiveStats(userId: string, guildId: string): Promise<EffectiveStats> {
+  const state = await ensurePlayerState(userId, guildId);
+  const { weapon, armor, cape } = await getEquipment(userId, guildId);
+  const w = parseItemProps(weapon?.props);
+  const a = parseItemProps(armor?.props);
+  const c = parseItemProps(cape?.props);
+
+  const mutW = await getMutationBonuses(userId, guildId, weapon?.id ?? null);
+  const mutA = await getMutationBonuses(userId, guildId, armor?.id ?? null);
+  const mutC = await getMutationBonuses(userId, guildId, cape?.id ?? null);
+
+  const damage = Math.max(0, (w.damage ?? 0) + mutW.damageBonus);
+  const defense = Math.max(0, (a.defense ?? 0) + mutA.defenseBonus);
+  const maxHp = Math.max(1, state.maxHp + (c.maxHpBonus ?? 0) + mutC.maxHpBonus);
+  const hp = Math.min(state.hp, maxHp);
+  return { damage, defense, maxHp, hp };
+}
+
+export async function adjustHP(userId: string, guildId: string, delta: number) {
+  const state = await ensurePlayerState(userId, guildId);
+  const { cape } = await getEquipment(userId, guildId);
+  const c = parseItemProps(cape?.props);
+  const maxHp = Math.max(1, state.maxHp + (c.maxHpBonus ?? 0));
+  const next = Math.min(maxHp, Math.max(0, state.hp + delta));
+  return prisma.playerState.update({ where: { userId_guildId: { userId, guildId } }, data: { hp: next, maxHp } });
+}