diff --git a/forge-game/src/main/java/forge/game/card/CardFactory.java b/forge-game/src/main/java/forge/game/card/CardFactory.java
index 331ffb1fd86..e3c7b524fb8 100644
--- a/forge-game/src/main/java/forge/game/card/CardFactory.java
+++ b/forge-game/src/main/java/forge/game/card/CardFactory.java
@@ -307,10 +307,13 @@ public class CardFactory {
             CardFactoryUtil.setupSiegeAbilities(card);
         }
         else if (card.getType().getBattleTypes().isEmpty()) {
+            //Probably a custom card? Check if it already has an RE for designating a protector.
+            if(card.getReplacementEffects().stream().anyMatch((re) -> re.hasParam("BattleProtector")))
+                return;
             //Battles with no battle type enter protected by their controller.
             String abProtector = "DB$ ChoosePlayer | Choices$ You | Protect$ True | DontNotify$ True";
             String reText = "Event$ Moved | ValidCard$ Card.Self | Destination$ Battlefield | ReplacementResult$ Updated"
-                    + " | Description$ (As this Battle enters, its controller becomes its protector.)";
+                    + " | BattleProtector$ True | Description$ (As this Battle enters, its controller becomes its protector.)";
             ReplacementEffect re = ReplacementHandler.parseReplacement(reText, card, true);
             re.setOverridingAbility(AbilityFactory.getAbility(abProtector, card));
             card.addReplacementEffect(re);
diff --git a/forge-game/src/main/java/forge/game/card/CardFactoryUtil.java b/forge-game/src/main/java/forge/game/card/CardFactoryUtil.java
index 8baaaa922bb..f34313ce5e8 100644
--- a/forge-game/src/main/java/forge/game/card/CardFactoryUtil.java
+++ b/forge-game/src/main/java/forge/game/card/CardFactoryUtil.java
@@ -4124,7 +4124,7 @@ public class CardFactoryUtil {
 
     public static void setupSiegeAbilities(Card card) {
         StringBuilder chooseSB = new StringBuilder();
-        chooseSB.append("Event$ Moved | ValidCard$ Card.Self | Destination$ Battlefield | ReplacementResult$ Updated");
+        chooseSB.append("Event$ Moved | ValidCard$ Card.Self | Destination$ Battlefield | ReplacementResult$ Updated | BattleProtector$ True");
         chooseSB.append(" | Description$ (As a Siege enters, choose an opponent to protect it. You and others can attack it. When it's defeated, exile it, then cast it transformed.)");
         String chooseProtector = "DB$ ChoosePlayer | Defined$ You | Choices$ Opponent | Protect$ True | ChoiceTitle$ Choose an opponent to protect this battle";