diff --git a/tests/MUnique.OpenMU.Tests/GameMapTest.cs b/tests/MUnique.OpenMU.Tests/GameMapTest.cs
index d1a5ac6..2cf21e2 100644
--- a/tests/MUnique.OpenMU.Tests/GameMapTest.cs
+++ b/tests/MUnique.OpenMU.Tests/GameMapTest.cs
@@ -165,6 +165,26 @@ public class GameMapTest
         Assert.That(player2.Object.Observers.Count, Is.EqualTo(0));
     }
 
+    /// <summary>
+    /// ADAMU-CUSTOM: remote-NPC — GetNpcByNumber, definition number ile spawn olmuş NPC'yi bulur;
+    /// bilinmeyen number için null döner. (upstream merge bu özelliği bozarsa bu test kırılır.)
+    /// </summary>
+    [Test]
+    public async ValueTask GetNpcByNumberFindsSpawnedNpcAsync()
+    {
+        var map = new GameMap(new GameMapDefinition(), TimeSpan.FromSeconds(60), ChunkSize);
+        var definition = new MUnique.OpenMU.DataModel.Configuration.MonsterDefinition { Number = 540 };
+        var spawnArea = new MUnique.OpenMU.DataModel.Configuration.MonsterSpawnArea { MonsterDefinition = definition };
+        var npc = new MUnique.OpenMU.GameLogic.NPC.NonPlayerCharacter(spawnArea, definition, map)
+        {
+            Position = new Point(100, 100),
+        };
+        await map.AddAsync(npc).ConfigureAwait(false);
+
+        Assert.That(map.GetNpcByNumber(540), Is.SameAs(npc));
+        Assert.That(map.GetNpcByNumber(999), Is.Null);
+    }
+
     private Mock<ITestPlayer> GetPlayer()
     {
         var player = new Mock<ITestPlayer>();