diff --git a/libraries/core/core-mc14w27a-mc1.14.4/src/main/java/net/ornithemc/osl/core/impl/mixin/common/IdentifierMixin.java b/libraries/core/core-mc14w27a-mc1.14.4/src/main/java/net/ornithemc/osl/core/impl/mixin/common/IdentifierMixin.java
index fd9ba778..15fef288 100644
--- a/libraries/core/core-mc14w27a-mc1.14.4/src/main/java/net/ornithemc/osl/core/impl/mixin/common/IdentifierMixin.java
+++ b/libraries/core/core-mc14w27a-mc1.14.4/src/main/java/net/ornithemc/osl/core/impl/mixin/common/IdentifierMixin.java
@@ -43,6 +43,11 @@ public String identifier() {
 		return path;
 	}
 
+	@Override
+	public Identifier namespaced(String namespace) {
+		return new Identifier(namespace, path);
+	}
+
 	@Override
 	public Identifier prefixed(String prefix) {
 		return new Identifier(namespace, prefix + path);
@@ -52,4 +57,14 @@ public Identifier prefixed(String prefix) {
 	public Identifier suffixed(String suffix) {
 		return new Identifier(namespace, path + suffix);
 	}
+
+	@Override
+	public Identifier subidentifier(int beginIndex) {
+		return new Identifier(namespace, path.substring(beginIndex));
+	}
+
+	@Override
+	public Identifier subidentifier(int beginIndex, int endIndex) {
+		return new Identifier(namespace, path.substring(beginIndex, endIndex));
+	}
 }
diff --git a/libraries/core/core-mc14w27a-mc1.14.4/src/main/java/net/ornithemc/osl/core/impl/util/IdentifierExtensionImpl.java b/libraries/core/core-mc14w27a-mc1.14.4/src/main/java/net/ornithemc/osl/core/impl/util/IdentifierExtensionImpl.java
index fdd50f99..e6174de7 100644
--- a/libraries/core/core-mc14w27a-mc1.14.4/src/main/java/net/ornithemc/osl/core/impl/util/IdentifierExtensionImpl.java
+++ b/libraries/core/core-mc14w27a-mc1.14.4/src/main/java/net/ornithemc/osl/core/impl/util/IdentifierExtensionImpl.java
@@ -16,6 +16,11 @@ default String identifier() {
 		throw new AbstractMethodError();
 	}
 
+	@Override
+	default Identifier namespaced(String namespace) {
+		throw new AbstractMethodError();
+	}
+
 	@Override
 	default Identifier prefixed(String prefix) {
 		throw new AbstractMethodError();
@@ -25,4 +30,14 @@ default Identifier prefixed(String prefix) {
 	default Identifier suffixed(String suffix) {
 		throw new AbstractMethodError();
 	}
+
+	@Override
+	default Identifier subidentifier(int beginIndex) {
+		throw new AbstractMethodError();
+	}
+
+	@Override
+	default Identifier subidentifier(int beginIndex, int endIndex) {
+		throw new AbstractMethodError();
+	}
 }
diff --git a/libraries/core/core-mca1.0.1_01-mc14w26c/src/main/java/net/ornithemc/osl/core/impl/mixin/client/IdentifierMixin.java b/libraries/core/core-mca1.0.1_01-mc14w26c/src/main/java/net/ornithemc/osl/core/impl/mixin/client/IdentifierMixin.java
index 3c02a22e..3745a469 100644
--- a/libraries/core/core-mca1.0.1_01-mc14w26c/src/main/java/net/ornithemc/osl/core/impl/mixin/client/IdentifierMixin.java
+++ b/libraries/core/core-mca1.0.1_01-mc14w26c/src/main/java/net/ornithemc/osl/core/impl/mixin/client/IdentifierMixin.java
@@ -47,6 +47,11 @@ public String identifier() {
 		return path;
 	}
 
+	@Override
+	public Identifier namespaced(String namespace) {
+		return new Identifier(namespace, path);
+	}
+
 	@Override
 	public Identifier prefixed(String prefix) {
 		return new Identifier(namespace, prefix + path);
@@ -56,4 +61,14 @@ public Identifier prefixed(String prefix) {
 	public Identifier suffixed(String suffix) {
 		return new Identifier(namespace, path + suffix);
 	}
+
+	@Override
+	public Identifier subidentifier(int beginIndex) {
+		return new Identifier(namespace, path.substring(beginIndex));
+	}
+
+	@Override
+	public Identifier subidentifier(int beginIndex, int endIndex) {
+		return new Identifier(namespace, path.substring(beginIndex, endIndex));
+	}
 }
diff --git a/libraries/core/core-mca1.0.1_01-mc14w26c/src/main/java/net/ornithemc/osl/core/impl/util/IdentifierExtensionImpl.java b/libraries/core/core-mca1.0.1_01-mc14w26c/src/main/java/net/ornithemc/osl/core/impl/util/IdentifierExtensionImpl.java
index 5822351c..b088d472 100644
--- a/libraries/core/core-mca1.0.1_01-mc14w26c/src/main/java/net/ornithemc/osl/core/impl/util/IdentifierExtensionImpl.java
+++ b/libraries/core/core-mca1.0.1_01-mc14w26c/src/main/java/net/ornithemc/osl/core/impl/util/IdentifierExtensionImpl.java
@@ -16,6 +16,11 @@ default String identifier() {
 		throw new AbstractMethodError();
 	}
 
+	@Override
+	default Identifier namespaced(String namespace) {
+		throw new AbstractMethodError();
+	}
+
 	@Override
 	default Identifier prefixed(String prefix) {
 		throw new AbstractMethodError();
@@ -25,4 +30,14 @@ default Identifier prefixed(String prefix) {
 	default Identifier suffixed(String suffix) {
 		throw new AbstractMethodError();
 	}
+
+	@Override
+	default Identifier subidentifier(int beginIndex) {
+		throw new AbstractMethodError();
+	}
+
+	@Override
+	default Identifier subidentifier(int beginIndex, int endIndex) {
+		throw new AbstractMethodError();
+	}
 }
diff --git a/libraries/core/src/main/java/net/ornithemc/osl/core/api/util/NamespacedIdentifier.java b/libraries/core/src/main/java/net/ornithemc/osl/core/api/util/NamespacedIdentifier.java
index 8871125b..c6054add 100644
--- a/libraries/core/src/main/java/net/ornithemc/osl/core/api/util/NamespacedIdentifier.java
+++ b/libraries/core/src/main/java/net/ornithemc/osl/core/api/util/NamespacedIdentifier.java
@@ -23,7 +23,14 @@ public interface NamespacedIdentifier {
 	 * The separator between the namespace and identifier in the {@code String}
 	 * representation of a {@code NamespacedIdentifier}.
 	 */
-	static char SEPARATOR = ':';
+	char SEPARATOR = ':';
+
+	/**
+	 * @return the separator for the {@linkplain String}-representation of this {@code NamespacedIdentifier}.
+	 */
+	default char separator() {
+		return SEPARATOR;
+	}
 
 	/**
 	 * @return the namespace of this {@code NamespacedIdentifier}.
@@ -35,6 +42,11 @@ public interface NamespacedIdentifier {
 	 */
 	String identifier();
 
+	/**
+	 * @return a copy of this {@code NamespacedIdentifier} with the given namespace.
+	 */
+	NamespacedIdentifier namespaced(String namespace);
+
 	/**
 	 * @return a copy of this {@code NamespacedIdentifier} with the given prefix.
 	 */
@@ -45,4 +57,14 @@ public interface NamespacedIdentifier {
 	 */
 	NamespacedIdentifier suffixed(String suffix);
 
+	/**
+	 * @return a copy of this {@code NamespacedIdentifier} that is a subidentifier of this identifier.
+	 */
+	NamespacedIdentifier subidentifier(int beginIndex);
+
+	/**
+	 * @return a copy of this {@code NamespacedIdentifier} that is a subidentifier of this identifier.
+	 */
+	NamespacedIdentifier subidentifier(int beginIndex, int endIndex);
+
 }
diff --git a/libraries/core/src/main/java/net/ornithemc/osl/core/api/util/NamespacedIdentifiers.java b/libraries/core/src/main/java/net/ornithemc/osl/core/api/util/NamespacedIdentifiers.java
index 75b4a1b3..77e96a42 100644
--- a/libraries/core/src/main/java/net/ornithemc/osl/core/api/util/NamespacedIdentifiers.java
+++ b/libraries/core/src/main/java/net/ornithemc/osl/core/api/util/NamespacedIdentifiers.java
@@ -140,7 +140,37 @@ public static String validateIdentifier(String identifier) {
 		return identifier;
 	}
 
+	/**
+	 * @return whether the given {@linkplain NamespacedIdentifier} is valid.
+	 */
+	public static boolean isValid(NamespacedIdentifier identifier) {
+		return isValidNamespace(identifier.namespace()) && isValidIdentifier(identifier.identifier());
+	}
+
+	/**
+	 * @return whether the given {@linkplain String} is a valid namespace.
+	 */
+	public static boolean isValidNamespace(String namespace) {
+		return namespace != null && !namespace.isEmpty()
+			&& namespace.chars().allMatch(chr -> chr == '-' || chr == '.' || chr == '_' || (chr >= 'a' && chr <= 'z') || (chr >= '0' && chr <= '9'));
+	}
+
+	/**
+	 * @return whether the given {@linkplain String} is a valid identifier.
+	 */
+	public static boolean isValidIdentifier(String identifier) {
+		return identifier != null && !identifier.isEmpty()
+			&& identifier.chars().allMatch(chr -> chr == '-' || chr == '.' || chr == '_' || chr == '/' || (chr >= 'a' && chr <= 'z') || (chr >= '0' && chr <= '9'));
+	}
+
+	/**
+	 * @return whether the given character is allowed in a {@linkplain NamespacedIdentifier}
+	 */
+	public static boolean isCharAllowed(int chr) {
+		return (chr == ':' || chr == '-' || chr == '.' || chr == '_' || chr == '/' || (chr >= 'a' && chr <= 'z') || (chr >= '0' && chr <= '9'));
+	}
+
 	public static boolean equals(NamespacedIdentifier a, NamespacedIdentifier b) {
-		return a.namespace().equals(b.namespace()) && a.identifier().equals(b.identifier());
+		return a.separator() == b.separator() && a.namespace().equals(b.namespace()) && a.identifier().equals(b.identifier());
 	}
 }
diff --git a/libraries/core/src/main/java/net/ornithemc/osl/core/impl/util/NamespacedIdentifierImpl.java b/libraries/core/src/main/java/net/ornithemc/osl/core/impl/util/NamespacedIdentifierImpl.java
index 9080f415..5d422ef7 100644
--- a/libraries/core/src/main/java/net/ornithemc/osl/core/impl/util/NamespacedIdentifierImpl.java
+++ b/libraries/core/src/main/java/net/ornithemc/osl/core/impl/util/NamespacedIdentifierImpl.java
@@ -55,6 +55,11 @@ public String identifier() {
 		return identifier;
 	}
 
+	@Override
+	public NamespacedIdentifier namespaced(String namespace) {
+		return new NamespacedIdentifierImpl(namespace, identifier);
+	}
+
 	@Override
 	public NamespacedIdentifier prefixed(String prefix) {
 		return new NamespacedIdentifierImpl(namespace, prefix + identifier);
@@ -64,4 +69,14 @@ public NamespacedIdentifier prefixed(String prefix) {
 	public NamespacedIdentifier suffixed(String suffix) {
 		return new NamespacedIdentifierImpl(namespace, identifier + suffix);
 	}
+
+	@Override
+	public NamespacedIdentifier subidentifier(int beginIndex) {
+		return new NamespacedIdentifierImpl(namespace, identifier.substring(beginIndex));
+	}
+
+	@Override
+	public NamespacedIdentifier subidentifier(int beginIndex, int endIndex) {
+		return new NamespacedIdentifierImpl(namespace, identifier.substring(beginIndex, endIndex));
+	}
 }