diff --git a/src/AcDream.App/Rendering/Vfx/EntityScriptActivator.cs b/src/AcDream.App/Rendering/Vfx/EntityScriptActivator.cs
index 828ccae..ad14615 100644
--- a/src/AcDream.App/Rendering/Vfx/EntityScriptActivator.cs
+++ b/src/AcDream.App/Rendering/Vfx/EntityScriptActivator.cs
@@ -68,6 +68,14 @@ public sealed class EntityScriptActivator
         uint scriptId = _defaultScriptResolver(entity);
         if (scriptId == 0) return;
 
+        // Seed the sink's per-entity rotation so CreateParticleHook.Offset.Origin
+        // (in entity-local frame) transforms correctly to world space when the
+        // hook fires. Without this, the sink falls through to Quaternion.Identity
+        // and the offset gets applied in world axes — visual symptom for portals:
+        // swirl oriented along world XYZ instead of the portal's facing, partially
+        // buried because the local-Z lift becomes a world-axis offset.
+        _particleSink.SetEntityRotation(entity.ServerGuid, entity.Rotation);
+
         _scriptRunner.Play(scriptId, entity.ServerGuid, entity.Position);
     }
 
diff --git a/tests/AcDream.Core.Tests/Rendering/Vfx/EntityScriptActivatorTests.cs b/tests/AcDream.Core.Tests/Rendering/Vfx/EntityScriptActivatorTests.cs
index d835e8c..e1e75f9 100644
--- a/tests/AcDream.Core.Tests/Rendering/Vfx/EntityScriptActivatorTests.cs
+++ b/tests/AcDream.Core.Tests/Rendering/Vfx/EntityScriptActivatorTests.cs
@@ -114,6 +114,64 @@ public sealed class EntityScriptActivatorTests
         EndAlpha       = 1f,
     };
 
+    [Fact]
+    public void OnCreate_SetsEntityRotationForHookOffsetTransform()
+    {
+        // The CreateParticleHook's Offset is in entity-local frame; the sink
+        // needs the entity's rotation to transform it to world space. If the
+        // activator forgets SetEntityRotation, the offset goes off in world
+        // axes — visual symptom: portal swirls misaligned to the portal stone.
+        // This test verifies the seed happens by checking the spawned particle's
+        // world position matches the rotated offset, not the unrotated offset.
+
+        var registry = new EmitterDescRegistry();
+        registry.Register(BuildPersistentEmitterDesc());
+
+        var system = new ParticleSystem(registry);
+        var hookSink = new ParticleHookSink(system);
+
+        // Hook offset = (1, 0, 0) in entity-local frame.
+        var hookOffset = new Frame
+        {
+            Origin = new Vector3(1f, 0f, 0f),
+            Orientation = Quaternion.Identity,
+        };
+        var script = BuildScript(
+            (0.0, new CreateParticleHook { EmitterInfoId = 100u, Offset = hookOffset }));
+        var table = new Dictionary<uint, DatPhysicsScript> { [0xAAu] = script };
+        var runner = new PhysicsScriptRunner(
+            id => table.TryGetValue(id, out var s) ? s : null,
+            hookSink);
+
+        var activator = new EntityScriptActivator(runner, hookSink, _ => 0xAAu);
+
+        // Entity rotated 90° around world-Z (yaw left); local +X maps to world +Y.
+        var entityRotation = Quaternion.CreateFromAxisAngle(
+            Vector3.UnitZ, MathF.PI / 2f);
+        var entity = new WorldEntity
+        {
+            Id = 0xCAFEu,
+            ServerGuid = 0xCAFEu,
+            SourceGfxObjOrSetupId = 0x02000001u,
+            Position = Vector3.Zero,
+            Rotation = entityRotation,
+            MeshRefs = System.Array.Empty<MeshRef>(),
+        };
+
+        activator.OnCreate(entity);
+        runner.Tick(0.001f);
+        system.Tick(0.001f);
+
+        // Find the live particle. With the rotation applied, world position of
+        // the local-(1,0,0) offset should be approximately world-(0,1,0). Without
+        // the rotation seed (the bug), it would be world-(1,0,0).
+        var live = system.EnumerateLive().FirstOrDefault();
+        Assert.NotNull(live.Emitter);
+        var worldPos = live.Emitter.Particles[live.Index].Position;
+        Assert.InRange(worldPos.X, -0.01f, 0.01f);
+        Assert.InRange(worldPos.Y,  0.99f, 1.01f);
+    }
+
     [Fact]
     public void OnRemove_StopsScriptsAndEmitters()
     {