diff --git a/Core/src/main/java/fr/pandacube/lib/core/permissions/Permissions.java b/Core/src/main/java/fr/pandacube/lib/core/permissions/Permissions.java
index 503908d..4fcf6c2 100644
--- a/Core/src/main/java/fr/pandacube/lib/core/permissions/Permissions.java
+++ b/Core/src/main/java/fr/pandacube/lib/core/permissions/Permissions.java
@@ -33,6 +33,14 @@ public class Permissions {
 			throw e;
 		}
 	}
+	
+	public static void addSpecialPermissions(SpecialPermission... specialPermissions) {
+		checkInitialized();
+		if (specialPermissions == null)
+			return;
+		for (SpecialPermission sp : specialPermissions)
+			resolver.specialPermissions.add(sp);
+	}
 
 	private static void checkInitialized() {
 		if (backendReader == null) {
diff --git a/Core/src/main/java/fr/pandacube/lib/core/permissions/PermissionsResolver.java b/Core/src/main/java/fr/pandacube/lib/core/permissions/PermissionsResolver.java
index 801e0a0..a4016c7 100644
--- a/Core/src/main/java/fr/pandacube/lib/core/permissions/PermissionsResolver.java
+++ b/Core/src/main/java/fr/pandacube/lib/core/permissions/PermissionsResolver.java
@@ -386,6 +386,12 @@ public class PermissionsResolver {
 	
 	
 	
+	
+	
+	/* package */ List<SpecialPermission> specialPermissions = new ArrayList<>();
+	
+	
+	
 	private PermResolutionNode resolveSelfPermission(CachedEntity entity, String permission, String server, String world) {
 		// special permissions
 		PermState result = PermState.UNDEFINED;
@@ -396,38 +402,15 @@ public class PermissionsResolver {
 		 * Check for special permissions
 		 */
 		if (entity instanceof CachedPlayer) {
-			PermPlayer permP = new PermPlayer(((CachedPlayer) entity).playerId);
+			PermPlayer permP = Permissions.getPlayer(((CachedPlayer) entity).playerId);
 			ParsedSelfPermission specialPerm = null;
-			if (permission.equals("pandacube.grade.isinstaff")) {
-				boolean res = permP.inheritsFromGroup("staff-base", true);
-				specialPerm = new ParsedSelfPermission(permission, res, PermType.SPECIAL);
-				conflict = "Special permission 'pandacube.grade.isinstaff' is deprecated. Use 'pandacube.inheritsfrom.<staffBaseGroup>' instead.";
-			}
-			else if (permission.startsWith("pandacube.grade.")) {
-				String group = permission.substring("pandacube.grade.".length());
-				boolean res = permP.inheritsFromGroup(group, false);
-				specialPerm = new ParsedSelfPermission(permission, res, PermType.SPECIAL);
-				conflict = "Special permission 'pandacube.grade.<groupName>' is deprecated. Use 'pandacube.ingroup.<groupName>' instead.";
-			}
-			else if (permission.startsWith("pandacube.ingroup.")) {
-				String group = permission.substring("pandacube.ingroup.".length());
-				boolean res = permP.inheritsFromGroup(group, false);
-				specialPerm = new ParsedSelfPermission(permission, res, PermType.SPECIAL);
-			}
-			else if (permission.startsWith("pandacube.inheritsfrom.")) {
-				String group = permission.substring("pandacube.inheritsfrom.".length());
-				boolean res = permP.inheritsFromGroup(group, true);
-				specialPerm = new ParsedSelfPermission(permission, res, PermType.SPECIAL);
-			}
-			else if (permission.startsWith("pandacube.inserver.")) {
-				String testedServer = permission.substring("pandacube.inserver.".length());
-				boolean res = testedServer.equals(server);
-				specialPerm = new ParsedSelfPermission(permission, res, PermType.SPECIAL);
-			}
-			else if (permission.startsWith("pandacube.inserverworld.")) {
-				String testedServerWorld = permission.substring("pandacube.inserverworld.".length());
-				boolean res = server != null && world != null && testedServerWorld.equals(server + "." + world);
-				specialPerm = new ParsedSelfPermission(permission, res, PermType.SPECIAL);
+			
+			for (SpecialPermission spePerm : specialPermissions) {
+				if (spePerm.match().match(permission)) {
+					boolean res = spePerm.tester().test(permP, permission, server, world);
+					specialPerm = new ParsedSelfPermission(permission, res, PermType.SPECIAL);
+					break;
+				}
 			}
 			
 			if (specialPerm != null) {
diff --git a/Core/src/main/java/fr/pandacube/lib/core/permissions/SpecialPermission.java b/Core/src/main/java/fr/pandacube/lib/core/permissions/SpecialPermission.java
new file mode 100644
index 0000000..d398c11
--- /dev/null
+++ b/Core/src/main/java/fr/pandacube/lib/core/permissions/SpecialPermission.java
@@ -0,0 +1,16 @@
+package fr.pandacube.lib.core.permissions;
+
+/**
+ * Represents a permission node that is based on an arbitrary player state.
+ */
+public record SpecialPermission(PermissionMatcher match, PermissionTester tester) {
+	
+	public interface PermissionMatcher {
+		boolean match(String permission);
+	}
+	
+	public interface PermissionTester {
+		boolean test(PermPlayer player, String permission, String server, String world);
+	}
+	
+}
diff --git a/Core/src/main/java/fr/pandacube/lib/core/players/PlayerFinder.java b/Core/src/main/java/fr/pandacube/lib/core/players/PlayerFinder.java
index cdcaa82..f2fae7a 100644
--- a/Core/src/main/java/fr/pandacube/lib/core/players/PlayerFinder.java
+++ b/Core/src/main/java/fr/pandacube/lib/core/players/PlayerFinder.java
@@ -33,7 +33,7 @@ import fr.pandacube.lib.core.util.Log;
 public class PlayerFinder {
 	
 	private static Cache<UUID, String> playerLastKnownName = CacheBuilder.newBuilder()
-			.expireAfterWrite(2, TimeUnit.MINUTES)
+			.expireAfterWrite(10, TimeUnit.MINUTES)
 			.maximumSize(1000)
 			.build();
 	
diff --git a/Core/src/main/java/fr/pandacube/lib/core/util/StringUtil.java b/Core/src/main/java/fr/pandacube/lib/core/util/StringUtil.java
index 8701942..11b47fc 100644
--- a/Core/src/main/java/fr/pandacube/lib/core/util/StringUtil.java
+++ b/Core/src/main/java/fr/pandacube/lib/core/util/StringUtil.java
@@ -1,5 +1,6 @@
 package fr.pandacube.lib.core.util;
 
+import java.util.Arrays;
 import java.util.List;
 
 public class StringUtil {
@@ -33,23 +34,11 @@ public class StringUtil {
 	
 	
 	
-
-	public static String repeat(String base, int count) {
-		int baseLength = base.length();
-		char[] baseChars = base.toCharArray();
-		char[] chars = new char[baseLength * count];
-		for (int i = 0; i < count; i++) {
-			System.arraycopy(baseChars, 0, chars, i * baseLength, baseLength);
-		}
-		return new String(chars);
-	}
 	
 	
 	public static String repeat(char base, int count) {
 		char[] chars = new char[count];
-		for (int i = 0; i < count; i++) {
-			chars[i] = base;
-		}
+		Arrays.fill(chars, base);
 		return new String(chars);
 	}
 }
diff --git a/Core/src/main/java/fr/pandacube/lib/core/util/TimeUtil.java b/Core/src/main/java/fr/pandacube/lib/core/util/TimeUtil.java
index f12cc9e..5a02894 100644
--- a/Core/src/main/java/fr/pandacube/lib/core/util/TimeUtil.java
+++ b/Core/src/main/java/fr/pandacube/lib/core/util/TimeUtil.java
@@ -215,7 +215,7 @@ public class TimeUtil {
 		int padding = leftPad - valueStr.length();
 		if (padding <= 0)
 			return valueStr;
-		return StringUtil.repeat("0", padding) + valueStr;
+		return "0".repeat(padding) + valueStr;
 	}