diff --git a/Engine.Core/Behaviour.cs b/Engine.Core/Behaviour.cs
index 34bf242..943d366 100644
--- a/Engine.Core/Behaviour.cs
+++ b/Engine.Core/Behaviour.cs
@@ -1,4 +1,5 @@
 using System;
+
 using Syntriax.Engine.Core.Abstract;
 using Syntriax.Engine.Core.Exceptions;
 
@@ -81,7 +82,6 @@ public abstract class Behaviour : IBehaviour
 
         _stateEnable = null!;
         _behaviourController = null!;
-        _stateEnable.Unassign();
 
         OnUnassigned?.Invoke(this);
         return true;
diff --git a/Engine.Core/BehaviourController.cs b/Engine.Core/BehaviourController.cs
index 76aa214..ef60e98 100644
--- a/Engine.Core/BehaviourController.cs
+++ b/Engine.Core/BehaviourController.cs
@@ -88,7 +88,7 @@ public class BehaviourController : IBehaviourController
 
     public bool Assign(IGameObject gameObject)
     {
-        if (GameObject.Initialized)
+        if (GameObject is not null && GameObject.Initialized)
             return false;
 
         _gameObject = gameObject;
@@ -98,7 +98,7 @@ public class BehaviourController : IBehaviourController
 
     public bool Unassign()
     {
-        if (GameObject.Initialized)
+        if (GameObject is not null && GameObject.Initialized)
             return false;
 
         _gameObject = null!;
diff --git a/Engine.Core/BehaviourOverride.cs b/Engine.Core/BehaviourOverride.cs
index 69189b9..0bc67d5 100644
--- a/Engine.Core/BehaviourOverride.cs
+++ b/Engine.Core/BehaviourOverride.cs
@@ -14,8 +14,12 @@ public abstract class BehaviourOverride : Behaviour
     {
         OnInitialized += OnInitialize;
         OnFinalized += OnFinalize;
+        OnUnassigned += OnUnassign;
     }
 
+    protected virtual void OnUnassign() { }
+    private void OnUnassign(IAssignable assignable) => OnUnassign();
+
     protected virtual void OnInitialize() { }
     private void OnInitialize(IInitialize _)
     {
diff --git a/Engine.Core/Behaviours/DrawableBehaviour.cs b/Engine.Core/Behaviours/DrawableBehaviour.cs
index 4b0784a..3a7a096 100644
--- a/Engine.Core/Behaviours/DrawableBehaviour.cs
+++ b/Engine.Core/Behaviours/DrawableBehaviour.cs
@@ -32,11 +32,11 @@ public class DrawableSpriteBehaviour : Behaviour, IDrawBehaviour, IAssignableSpr
 
     public bool Assign(ISprite sprite)
     {
-        if (Initialized)
-            return false;
-
         _sprite = sprite;
         OnSpriteAssigned?.Invoke(this);
         return true;
     }
+
+    public DrawableSpriteBehaviour() => OnUnassigned += OnUnassign;
+    private void OnUnassign(IAssignable assignable) => _sprite = null!;
 }
diff --git a/Engine.Core/StateEnable.cs b/Engine.Core/StateEnable.cs
index cf38305..70256ca 100644
--- a/Engine.Core/StateEnable.cs
+++ b/Engine.Core/StateEnable.cs
@@ -30,7 +30,7 @@ public class StateEnable : IStateEnable
 
     public bool Assign(IEntity entity)
     {
-        if (_entity.Initialized)
+        if (_entity is not null && _entity.Initialized)
             return false;
 
         _entity = entity;