diff --git a/src/gaemstone.SourceGen/ModuleGenerator.cs b/src/gaemstone.SourceGen/ModuleGenerator.cs
index 825500f..e4f3b6a 100644
--- a/src/gaemstone.SourceGen/ModuleGenerator.cs
+++ b/src/gaemstone.SourceGen/ModuleGenerator.cs
@@ -209,8 +209,10 @@ public class ModuleGenerator
 				sb.AppendLine("\t\t\t\tnew(");
 				foreach (var p in m.Parameters)
 					if (p.HasTerm) {
-						// TODO: Throw error if multiple Or terms appear next to each other.
-						foreach (var term in p.TermTypes) {
+						for (var i = 0; i < p.TermTypes.Count; i++) {
+							var term = p.TermTypes[i];
+							var isLastTerm = (i == p.TermTypes.Count - 1);
+
 							sb.Append($"\t\t\t\t\tnew Term(");
 							switch (term) {
 								case ITypeSymbol type:
@@ -225,14 +227,17 @@ public class ModuleGenerator
 									$"Unexpected term type {term.GetType()}");
 							}
 							sb.Append(')');
+
 							if (p.Source != null) {
 								sb.Append("{ Source = ");
 								AppendTypeEntity(sb, module, p.Source);
 								sb.Append(" }");
 							}
+
+							// The last term in a group of OR terms must not have the TermOperKind.Or set.
+							if (p.IsOr && !isLastTerm) sb.Append(".Or");
+
 							sb.Append(p.Kind switch {
-								ParameterKind.Or    => ".Or",
-								ParameterKind.HasOr => ".Or.None",
 								ParameterKind.Has => ".None",
 								ParameterKind.Not => ".None.Not",
 								ParameterKind.Ref => ".InOut",
@@ -240,7 +245,9 @@ public class ModuleGenerator
 								_ when !p.IsValueType => ".InOut", // Reference types always imply writability.
 								_ => ".In",
 							});
+
 							if (p.IsNullable) sb.Append(".Optional");
+
 							sb.AppendLine(",");
 						}
 					}
@@ -317,6 +324,9 @@ public class ModuleGenerator
 		if (method.IsGeneric) sb.Append("<T>");
 		sb.Append($"(");
 		foreach (var param in method.Parameters) {
+			// TODO: Support [Or<...>]
+			if (param.IsOr && (param.Kind != ParameterKind.Has))
+				throw new NotSupportedException($"Or<...> parameter not yet supported");
 			switch (param.Kind) {
 				case ParameterKind.Unique:
 					sb.Append(param.UniqueReplacement);
@@ -338,13 +348,8 @@ public class ModuleGenerator
 
 				case ParameterKind.Has:
 				case ParameterKind.Not:
-				case ParameterKind.HasOr:
 					sb.Append("default");
 					break;
-
-				case ParameterKind.Or:
-					throw new NotSupportedException(
-						$"ParameterKind {param.Kind} not supported");
 			}
 			sb.Append(", ");
 		}
@@ -363,6 +368,7 @@ public class ModuleGenerator
 		StringBuilder sb, ModuleEntityInfo module,
 		ITypeSymbol type)
 	{
+		// TODO: Cache entity lookup.
 		var found = module.Children.Where(c => !c.IsErrored)
 			.Any(c => SymbolEqualityComparer.Default.Equals(c.Symbol, type));
 		sb.Append(found ? $"_{type.Name}_Entity"
diff --git a/src/gaemstone.SourceGen/Structure/ParameterInfo.cs b/src/gaemstone.SourceGen/Structure/ParameterInfo.cs
index aa8177c..6615c6a 100644
--- a/src/gaemstone.SourceGen/Structure/ParameterInfo.cs
+++ b/src/gaemstone.SourceGen/Structure/ParameterInfo.cs
@@ -35,9 +35,10 @@ public class ParameterInfo : BaseInfo
 	public IReadOnlyList<object> TermTypes { get; } // Either ITypeSymbol or Pair for relationships.
 	public ITypeSymbol? FieldType { get; }
 	public ParameterKind Kind { get; }
+	public bool IsOr { get; }
 
 	public bool HasTerm  => (Kind != ParameterKind.Unique);
-	public bool HasField => HasTerm && !(Kind is ParameterKind.Has or ParameterKind.Not or ParameterKind.HasOr);
+	public bool HasField => HasTerm && !(Kind is ParameterKind.Has or ParameterKind.Not);
 
 	public ParameterInfo(ISymbol symbol)
 		: base(symbol)
@@ -49,15 +50,16 @@ public class ParameterInfo : BaseInfo
 		var typeFullName = Symbol.Type.GetFullName(FullNameStyle.Metadata);
 		if (UniqueParameters.TryGetValue(typeFullName, out var replacement))
 		{
+			IsOr = false;
 			Kind = ParameterKind.Unique;
 			TermTypes = Array.Empty<ITypeSymbol>();
 			UniqueReplacement = replacement;
 		}
 		else
 		{
+			IsOr = typeFullName.StartsWith("gaemstone.ECS.Or");
 			var isHas = typeFullName.StartsWith("gaemstone.ECS.Has");
 			var isNot = typeFullName.StartsWith("gaemstone.ECS.Not");
-			var isOr  = typeFullName.StartsWith("gaemstone.ECS.Or");
 
 			if (IsGeneric)
 			{
@@ -71,7 +73,7 @@ public class ParameterInfo : BaseInfo
 				{
 					TermTypes = argType.TypeArguments.ToImmutableList();
 					FieldType = null;
-					isOr = true;
+					IsOr = true;
 				}
 				else if ((isHas || isNot) && (args is [ INamedTypeSymbol relation, INamedTypeSymbol target ]))
 				{
@@ -90,11 +92,9 @@ public class ParameterInfo : BaseInfo
 				FieldType = Symbol.Type;
 			}
 
-			Kind = (isHas && isOr) ? ParameterKind.HasOr
-				:   isHas          ? ParameterKind.Has
-				:   isOr           ? ParameterKind.Or
-				:   isNot          ? ParameterKind.Not
-				:   IsNullable     ? ParameterKind.Nullable
+			Kind = isHas          ? ParameterKind.Has
+				:  isNot          ? ParameterKind.Not
+				:  IsNullable     ? ParameterKind.Nullable
 				: Symbol.RefKind switch {
 					RefKind.In    => ParameterKind.In,
 					RefKind.Out   => ParameterKind.Out,
@@ -141,8 +141,7 @@ public class ParameterInfo : BaseInfo
 		}
 		else
 		{
-			var isSpecial = Kind is ParameterKind.Has or ParameterKind.HasOr
-			                     or ParameterKind.Or  or ParameterKind.Not;
+			var isSpecial = IsOr || (Kind is ParameterKind.Has or ParameterKind.Not);
 			if (isSpecial && IsByRef) yield return Diagnostic.Create(
 				Descriptors.SpecialMustNotBeByRef, Location);
 			if (isSpecial && IsNullable) yield return Diagnostic.Create(
@@ -202,8 +201,6 @@ public enum ParameterKind
 	Ref, // Pass by reference (read/write)
 	Has, // Required present (no read/write)
 	Not, // Required missing (no read/write)
-	Or,  // Only one of multiple terms is required
-	HasOr, // Both Has and Or at the same time
 }
 
 // public enum TermKind