diff --git a/src/core/event/AbilityEvent.java b/src/core/event/AbilityEvent.java
index ed3365cc486bb15dc21ca03a8debcb2bbacb7b86..6c289491d481a6cbc281c556bed0f088ced2e6ed 100644
--- a/src/core/event/AbilityEvent.java
+++ b/src/core/event/AbilityEvent.java
@@ -12,7 +12,7 @@ import java.util.List;
 /**
  * Created by dupriez on 19/12/15.
  */
-public class AbilityEvent implements core.event.Event {
+public class AbilityEvent implements ClientEvent,ServerEvent {
 
 	private static final long serialVersionUID = 1L;
 	private int potentialCasterCharacterID;
diff --git a/src/core/event/ClientEvent.java b/src/core/event/ClientEvent.java
new file mode 100644
index 0000000000000000000000000000000000000000..d9b5005d620dd4e119d555bec91b8fa68b2fbc65
--- /dev/null
+++ b/src/core/event/ClientEvent.java
@@ -0,0 +1,10 @@
+package core.event;
+
+/**
+ * Only used to add some security between event. Those event can be sent by the server to the client.
+ * @author Guerquin Arnaud
+ *
+ */
+public interface ClientEvent extends Event {
+
+}
diff --git a/src/core/event/CreationEvent.java b/src/core/event/CreationEvent.java
index 95e75a1ac932c54b3662a3700139176734936ed6..e7181037844006daff92c7ec8380ec07485e6f38 100644
--- a/src/core/event/CreationEvent.java
+++ b/src/core/event/CreationEvent.java
@@ -8,7 +8,7 @@ import core.gamestate.GameContent;
  * @author Guerquin Arnaud
  *
  */
-public class CreationEvent implements Event {
+public class CreationEvent implements ClientEvent {
 
 	private static final long serialVersionUID = 1L;
 
diff --git a/src/core/event/DeathEvent.java b/src/core/event/DeathEvent.java
index b10354a5218a56376b106a501e8b3c839db1f0d8..ce7e49176c9876111b38a784930a7e79555026e3 100644
--- a/src/core/event/DeathEvent.java
+++ b/src/core/event/DeathEvent.java
@@ -7,7 +7,7 @@ import core.gamestate.GameContent;
  * @author Guerquin Arnaud
  *
  */
-public class DeathEvent implements Event {
+public class DeathEvent implements ClientEvent {
 
 	private static final long serialVersionUID = 1L;
 	@Override
diff --git a/src/core/event/EmptyEvent.java b/src/core/event/EmptyEvent.java
index 3b2d307eebb1f457064716de9da6203403776269..30b9ea9c11fe65cd0ae0c53274ca2ffee99a79f2 100644
--- a/src/core/event/EmptyEvent.java
+++ b/src/core/event/EmptyEvent.java
@@ -8,7 +8,7 @@ import core.gamestate.GameContent;
  * @author Guerquin Arnaud
  *
  */
-public class EmptyEvent implements Event {
+public class EmptyEvent implements ClientEvent,ServerEvent {
 
 	private static final long serialVersionUID = 1L;
 	public static final EmptyEvent empty=new EmptyEvent();
diff --git a/src/core/event/Event.java b/src/core/event/Event.java
index 304fc98ecfedfe90b6b98483db546529c1d2986e..5821f2212847359cdbd2604a00abb325a51b264a 100644
--- a/src/core/event/Event.java
+++ b/src/core/event/Event.java
@@ -14,17 +14,6 @@ public interface Event extends NetworkObject{
 
 	static final long serialVersionUID = 1L;
 	public static final int infinity = -1;
-
-	
-	/**
-	 * Give a modified version of the first event using the second.
-	 * @param event the event applied to this. Can't be null.
-	 * @return true if a modification happened. 
-	 */
-	public default boolean alter(Event event){
-		return false;
-	}
-
 	
 	boolean execute(GameContent gameContent);
 
diff --git a/src/core/event/FailedEvent.java b/src/core/event/FailedEvent.java
index e7cf06ee78b51ffe4d66f501495a493433025685..2dec3517d088002ed93231040dcee0d1d2790d57 100644
--- a/src/core/event/FailedEvent.java
+++ b/src/core/event/FailedEvent.java
@@ -8,7 +8,7 @@ import core.gamestate.GameContent;
  * @author Guerquin Arnaud
  *
  */
-public class FailedEvent implements Event{
+public class FailedEvent implements ClientEvent,ServerEvent{
 	
 	private static final long serialVersionUID = 1L;
 	static final public Event failed=new FailedEvent();
diff --git a/src/core/event/MapInit.java b/src/core/event/MapInit.java
index 8a5d7422f0d81c8c4e1b412353e9a07e29b8d62a..c60478d35dc0b723013f6f235c431393e31bfbdb 100644
--- a/src/core/event/MapInit.java
+++ b/src/core/event/MapInit.java
@@ -11,7 +11,7 @@ import gameloop.DummyLocalGameLoop;
  *	An Event that changes the map and the gameState
  *
  */
-public class MapInit implements Event {
+public class MapInit implements ClientEvent {
 
 	private static final long serialVersionUID = 1L;
 	private GameContent  gameContent;
diff --git a/src/core/event/MoveEvent.java b/src/core/event/MoveEvent.java
index 76cd67f34dac7481b49bd6a0b796719109f7a769..4c63082e9f7ec39661828cd9f3a863a07a445ced 100644
--- a/src/core/event/MoveEvent.java
+++ b/src/core/event/MoveEvent.java
@@ -12,7 +12,7 @@ import core.zone.Translation;
  * @author Guerquin Arnaud
  *
  */
-public class MoveEvent implements Event {
+public class MoveEvent implements ClientEvent,ServerEvent {
 
 	private static final long serialVersionUID = 1L;
 	private int targetID;
diff --git a/src/core/event/ServerEvent.java b/src/core/event/ServerEvent.java
new file mode 100644
index 0000000000000000000000000000000000000000..1a7e82a82a92ca28b496f29d472a330ca199d727
--- /dev/null
+++ b/src/core/event/ServerEvent.java
@@ -0,0 +1,10 @@
+package core.event;
+
+/**
+ * Only used to add some security between event. Those event can be sent by the client to the server.
+ * @author Guerquin Arnaud
+ *
+ */
+public interface ServerEvent extends Event {
+
+}
diff --git a/src/core/event/StairsEvent.java b/src/core/event/StairsEvent.java
deleted file mode 100644
index 1cd898668c415a938ea85e3f394f6e69466dcae1..0000000000000000000000000000000000000000
--- a/src/core/event/StairsEvent.java
+++ /dev/null
@@ -1,26 +0,0 @@
-package core.event;
-
-
-import core.gamestate.GameContent;
-import gameloop.GameStarter;
-
-//created by Theodore LOPEZ just for tests on stairs
-
-public class StairsEvent implements Event {
-
-	private static final long serialVersionUID = 1L;
-	public StairsEvent(){
-	}
-	
-	@Override
-	public boolean execute(GameContent gameContent) {
-		GameStarter.leaveGame();
-		return true;
-	}
-
-	@Override
-	public Event resolve(GameContent gameContent) {
-		return this;
-	}
-
-}