diff --git a/src/AcDream.App/UI/IconComposer.cs b/src/AcDream.App/UI/IconComposer.cs
index fc2c87aa..516b8e9b 100644
--- a/src/AcDream.App/UI/IconComposer.cs
+++ b/src/AcDream.App/UI/IconComposer.cs
@@ -43,6 +43,15 @@ public sealed class IconComposer
     private bool _underlayResolveTried;
     private readonly Dictionary<uint, uint> _underlayDidByIndex = new();
 
+    // ── effect overlay resolve (EnumIDMap 0x10000005) ────────────────────────
+    // Portal MasterMap (0x25000000) maps enum 0x10000005 → submap DID (0x25000009).
+    // Submap maps index → 0x06 RenderSurface DID.  index = LSB(effects)+1, fallback 0x21.
+    // Refs: IconData::RenderIcons 0x0058d180 (effect path); the effect tile is a
+    // ReplaceColor tint SOURCE, not a blit layer (see RESOLVED doc, divergence DR-1).
+    private EnumIDMap? _effectSubMap;
+    private bool _effectResolveTried;
+    private readonly Dictionary<uint, uint> _effectDidByIndex = new();
+
     public IconComposer(DatCollection dats, TextureCache cache)
     {
         _dats = dats;
@@ -84,6 +93,38 @@ public sealed class IconComposer
         if (_dats.Portal.TryGet<EnumIDMap>(subDid, out var sub)) _underlaySubMap = sub;
     }
 
+    /// <summary>
+    /// Resolve the effect-overlay DID for <paramref name="effects"/> via the EnumIDMap
+    /// 0x10000005 chain. index = LowestSetBit(effects)+1; if the entry is missing/zero,
+    /// retail falls back to index 0x21 (the solid-black tile). NOTE: the effect path has
+    /// NO lsb==-1 pre-check (unlike the type underlay), so effects==0 → index 0 → miss →
+    /// fallback. (Retail IconData::RenderIcons 0x0058d180.)
+    /// </summary>
+    internal uint ResolveEffectDid(uint effects)
+    {
+        int lsb = effects == 0 ? -1 : BitOperations.TrailingZeroCount(effects);
+        uint index = (uint)(lsb + 1);
+        if (_effectDidByIndex.TryGetValue(index, out var cached)) return cached;
+        EnsureEffectSubMap();
+        uint did = 0;
+        if (_effectSubMap is { } sub && sub.ClientEnumToID.TryGetValue(index, out var d)) did = d;
+        if (did == 0 && _effectSubMap is { } sub2 && sub2.ClientEnumToID.TryGetValue(0x21u, out var fb))
+            did = fb;
+        _effectDidByIndex[index] = did;
+        return did;
+    }
+
+    private void EnsureEffectSubMap()
+    {
+        if (_effectResolveTried) return;
+        _effectResolveTried = true;
+        uint masterDid = (uint)_dats.Portal.Header.MasterMapId;   // = 0x25000000
+        if (masterDid == 0) return;
+        if (!_dats.Portal.TryGet<EnumIDMap>(masterDid, out var master)) return;
+        if (!master.ClientEnumToID.TryGetValue(0x10000005u, out var subDid)) return;  // → 0x25000009
+        if (_dats.Portal.TryGet<EnumIDMap>(subDid, out var sub)) _effectSubMap = sub;
+    }
+
     /// <summary>Pure alpha-over composite, bottom-&gt;top. Layers may differ in size;
     /// the result is sized to the FIRST (bottom) layer and upper layers are sampled
     /// top-left aligned (all icon layers are 32x32 in practice).</summary>
diff --git a/tests/AcDream.App.Tests/UI/IconComposerTests.cs b/tests/AcDream.App.Tests/UI/IconComposerTests.cs
index 06a225e5..4a19ed83 100644
--- a/tests/AcDream.App.Tests/UI/IconComposerTests.cs
+++ b/tests/AcDream.App.Tests/UI/IconComposerTests.cs
@@ -101,4 +101,29 @@ public class IconComposerTests
         Assert.Equal(0x060011D5u, composer.ResolveUnderlayDid(ItemType.Jewelry));
         Assert.Equal(0x060011D4u, composer.ResolveUnderlayDid(ItemType.None));
     }
+
+    [Fact]
+    public void ResolveEffectDid_goldenValues_matchDat()
+    {
+        var datDir = ResolveDatDir();
+        if (datDir is null) return;  // dats absent (CI) — skip cleanly
+
+        using var dats = new DatCollection(datDir, DatAccessType.Read);
+        var composer = new IconComposer(dats, null!);
+
+        // Golden values (live dat, MasterMap 0x25000000 → effect submap 0x25000009;
+        // index = LowestSetBit(UiEffects)+1, fallback 0x21):
+        //   Magical      (0x0001) → idx 1  → 0x060011CA
+        //   Poisoned     (0x0002) → idx 2  → 0x060011C6
+        //   BoostHealth  (0x0004) → idx 3  → 0x06001B05
+        //   BoostStamina (0x0010) → idx 5  → 0x06001B06
+        //   Nether       (0x1000) → idx 13 (absent) → fallback 0x21 → 0x060011C5
+        //   none         (0x0000) → idx 0  (zero)   → fallback 0x21 → 0x060011C5
+        Assert.Equal(0x060011CAu, composer.ResolveEffectDid(0x0001u));
+        Assert.Equal(0x060011C6u, composer.ResolveEffectDid(0x0002u));
+        Assert.Equal(0x06001B05u, composer.ResolveEffectDid(0x0004u));
+        Assert.Equal(0x06001B06u, composer.ResolveEffectDid(0x0010u));
+        Assert.Equal(0x060011C5u, composer.ResolveEffectDid(0x1000u));
+        Assert.Equal(0x060011C5u, composer.ResolveEffectDid(0x0000u));
+    }
 }