diff --git a/src/main/java/net/minestom/server/item/metadata/CrossbowMeta.java b/src/main/java/net/minestom/server/item/metadata/CrossbowMeta.java
index 47df6d363..cfc525f2f 100644
--- a/src/main/java/net/minestom/server/item/metadata/CrossbowMeta.java
+++ b/src/main/java/net/minestom/server/item/metadata/CrossbowMeta.java
@@ -11,8 +11,8 @@ import org.jetbrains.annotations.UnknownNullability;
 import java.util.List;
 
 public record CrossbowMeta(TagReadable readable) implements ItemMetaView<CrossbowMeta.Builder> {
-    private static final Tag<List<ItemStack>> PROJECTILES = Tag.ItemStack("ChargedProjectiles").list();
-    private static final Tag<Boolean> CHARGED = Tag.Boolean("Charged");
+    private static final Tag<List<ItemStack>> PROJECTILES = Tag.ItemStack("ChargedProjectiles").list().defaultValue(List.of());
+    private static final Tag<Boolean> CHARGED = Tag.Boolean("Charged").defaultValue(false);
 
     public @NotNull List<ItemStack> getProjectiles() {
         return getTag(PROJECTILES);
diff --git a/src/main/java/net/minestom/server/item/metadata/FireworkMeta.java b/src/main/java/net/minestom/server/item/metadata/FireworkMeta.java
index 1654a02cd..722057271 100644
--- a/src/main/java/net/minestom/server/item/metadata/FireworkMeta.java
+++ b/src/main/java/net/minestom/server/item/metadata/FireworkMeta.java
@@ -7,6 +7,7 @@ import net.minestom.server.tag.TagHandler;
 import net.minestom.server.tag.TagReadable;
 import net.minestom.server.tag.TagSerializer;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 import org.jetbrains.annotations.UnknownNullability;
 
 import java.util.List;
@@ -17,11 +18,11 @@ public record FireworkMeta(TagReadable readable) implements ItemMetaView<Firewor
             .path("Fireworks").list().defaultValue(List.of());
     private static final Tag<Byte> FLIGHT_DURATION = Tag.Byte("Flight").path("Fireworks");
 
-    public List<FireworkEffect> getEffects() {
+    public @NotNull List<FireworkEffect> getEffects() {
         return getTag(EFFECTS);
     }
 
-    public byte getFlightDuration() {
+    public @Nullable Byte getFlightDuration() {
         return getTag(FLIGHT_DURATION);
     }
 
diff --git a/src/main/java/net/minestom/server/item/metadata/PlayerHeadMeta.java b/src/main/java/net/minestom/server/item/metadata/PlayerHeadMeta.java
index c9b8fc268..6dd857a56 100644
--- a/src/main/java/net/minestom/server/item/metadata/PlayerHeadMeta.java
+++ b/src/main/java/net/minestom/server/item/metadata/PlayerHeadMeta.java
@@ -42,7 +42,7 @@ public record PlayerHeadMeta(TagReadable readable) implements ItemMetaView<Playe
         }
     }).path("SkullOwner");
 
-    public UUID getSkullOwner() {
+    public @Nullable UUID getSkullOwner() {
         return getTag(SKULL_OWNER);
     }
 
diff --git a/src/main/java/net/minestom/server/item/metadata/PotionMeta.java b/src/main/java/net/minestom/server/item/metadata/PotionMeta.java
index f69d0bb27..5b2b08899 100644
--- a/src/main/java/net/minestom/server/item/metadata/PotionMeta.java
+++ b/src/main/java/net/minestom/server/item/metadata/PotionMeta.java
@@ -13,7 +13,7 @@ import org.jetbrains.annotations.UnknownNullability;
 import java.util.List;
 
 public record PotionMeta(TagReadable readable) implements ItemMetaView<PotionMeta.Builder> {
-    private static final Tag<PotionType> POTION_TYPE = Tag.String("Potion").map(PotionType::fromNamespaceId, ProtocolObject::name);
+    private static final Tag<PotionType> POTION_TYPE = Tag.String("Potion").map(PotionType::fromNamespaceId, ProtocolObject::name).defaultValue(PotionType.EMPTY);
     private static final Tag<List<CustomPotionEffect>> CUSTOM_POTION_EFFECTS = Tag.Structure("CustomPotionEffects", new TagSerializer<CustomPotionEffect>() {
         @Override
         public @Nullable CustomPotionEffect read(@NotNull TagReadable reader) {
@@ -41,15 +41,15 @@ public record PotionMeta(TagReadable readable) implements ItemMetaView<PotionMet
     }).list().defaultValue(List.of());
     private static final Tag<Color> CUSTOM_POTION_COLOR = Tag.Integer("CustomPotionColor").path("display").map(Color::new, Color::asRGB);
 
-    public PotionType getPotionType() {
+    public @NotNull PotionType getPotionType() {
         return getTag(POTION_TYPE);
     }
 
-    public List<CustomPotionEffect> getCustomPotionEffects() {
+    public @NotNull List<CustomPotionEffect> getCustomPotionEffects() {
         return getTag(CUSTOM_POTION_EFFECTS);
     }
 
-    public Color getColor() {
+    public @Nullable Color getColor() {
         return getTag(CUSTOM_POTION_COLOR);
     }
 
diff --git a/src/main/java/net/minestom/server/item/metadata/WrittenBookMeta.java b/src/main/java/net/minestom/server/item/metadata/WrittenBookMeta.java
index da0adc77f..a295ba70d 100644
--- a/src/main/java/net/minestom/server/item/metadata/WrittenBookMeta.java
+++ b/src/main/java/net/minestom/server/item/metadata/WrittenBookMeta.java
@@ -14,7 +14,7 @@ import java.util.Arrays;
 import java.util.List;
 
 public record WrittenBookMeta(TagReadable readable) implements ItemMetaView<WrittenBookMeta.Builder> {
-    private static final Tag<Boolean> RESOLVED = Tag.Boolean("resolved");
+    private static final Tag<Boolean> RESOLVED = Tag.Boolean("resolved").defaultValue(false);
     private static final Tag<WrittenBookGeneration> GENERATION = Tag.Integer("resolved").map(integer -> WrittenBookGeneration.values()[integer], Enum::ordinal);
     private static final Tag<String> AUTHOR = Tag.String("author");
     private static final Tag<String> TITLE = Tag.String("title");
diff --git a/src/main/java/net/minestom/server/tag/Tag.java b/src/main/java/net/minestom/server/tag/Tag.java
index 97c0b89ab..ab3b72c5d 100644
--- a/src/main/java/net/minestom/server/tag/Tag.java
+++ b/src/main/java/net/minestom/server/tag/Tag.java
@@ -106,7 +106,11 @@ public class Tag<T> {
         return new Tag<>(index, key, readMap,
                 new Serializers.Entry<>(readFunction, writeFunction),
                 // Default value
-                () -> readMap.apply(createDefault()),
+                () -> {
+                    T defaultValue = createDefault();
+                    if (defaultValue == null) return null;
+                    return readMap.apply(defaultValue);
+                },
                 path, null, listScope);
     }
 
diff --git a/src/test/java/net/minestom/server/tag/TagMapTest.java b/src/test/java/net/minestom/server/tag/TagMapTest.java
index b06a10974..08595008d 100644
--- a/src/test/java/net/minestom/server/tag/TagMapTest.java
+++ b/src/test/java/net/minestom/server/tag/TagMapTest.java
@@ -3,6 +3,7 @@ package net.minestom.server.tag;
 import org.junit.jupiter.api.Test;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
 
 public class TagMapTest {
 
@@ -32,4 +33,11 @@ public class TagMapTest {
         assertEquals(2, handler.getTag(intTag));
         assertEquals(new Entry(2), handler.getTag(tag));
     }
+
+    @Test
+    public void mapDefaultAbsent() {
+        var handler = TagHandler.newHandler();
+        var tag = Tag.Integer("key").map(Entry::new, Entry::value);
+        assertNull(handler.getTag(tag));
+    }
 }