diff --git a/src/OpenRpg.Core/Types/EntityStateVariableTypes.cs b/src/OpenRpg.Core/Types/EntityStateVariableTypes.cs
new file mode 100644
index 0000000..b39c45d
--- /dev/null
+++ b/src/OpenRpg.Core/Types/EntityStateVariableTypes.cs
@@ -0,0 +1,7 @@
+namespace OpenRpg.Core.Types
+{
+    public interface EntityStateVariableTypes
+    {
+        public static readonly int Unknown = 0;
+    }
+}
\ No newline at end of file
diff --git a/src/OpenRpg.Core/Types/StatsVariableTypes.cs b/src/OpenRpg.Core/Types/StatsVariableTypes.cs
new file mode 100644
index 0000000..6c3b051
--- /dev/null
+++ b/src/OpenRpg.Core/Types/StatsVariableTypes.cs
@@ -0,0 +1,7 @@
+namespace OpenRpg.Core.Types
+{
+    public interface StatsVariableTypes
+    {
+        public static readonly int Unknown = 0;
+    }
+}
\ No newline at end of file