diff --git a/OECS.SourceGen/ComponentDiscoveryGenerator.cs b/OECS.SourceGen/ComponentDiscoveryGenerator.cs
index 21a5b45..39235d9 100644
--- a/OECS.SourceGen/ComponentDiscoveryGenerator.cs
+++ b/OECS.SourceGen/ComponentDiscoveryGenerator.cs
@@ -53,10 +53,7 @@ public class ComponentDiscoveryGenerator : IIncrementalGenerator
         "RemoveSingleton",
     };
 
-    private static readonly HashSet<string> _forEachNames = new()
-    {
-        "ForEach",
-    };
+
 
     public void Initialize(IncrementalGeneratorInitializationContext context)
     {
@@ -68,15 +65,7 @@ public class ComponentDiscoveryGenerator : IIncrementalGenerator
             .Where(t => t.FullyQualifiedName != null)
             .Select((t, _) => (t.FullyQualifiedName!, t.AssemblyQualifiedName!, t.IsRelationship, t.IsSingleton));
 
-        // Also collect ForEach type arguments from the World class.
-        var forEachCalls = context.SyntaxProvider
-            .CreateSyntaxProvider(
-                predicate: IsForEachCandidate,
-                transform: ExtractForEachTypes)
-            .Where(list => list.Length > 0)
-            .SelectMany((list, _) => list);
-
-        var allTypes = invocations.Collect().Combine(forEachCalls.Collect());
+        var allTypes = invocations.Collect();
 
         context.RegisterSourceOutput(allTypes, GenerateRegistry);
     }
@@ -97,21 +86,7 @@ public class ComponentDiscoveryGenerator : IIncrementalGenerator
         return false;
     }
 
-    private static bool IsForEachCandidate(SyntaxNode node, CancellationToken _)
-    {
-        if (node is not InvocationExpressionSyntax invocation)
-            return false;
 
-        if (invocation.Expression is MemberAccessExpressionSyntax memberAccess)
-        {
-            var name = memberAccess.Name is GenericNameSyntax gn
-                ? gn.Identifier.Text
-                : memberAccess.Name.Identifier.Text;
-            return _forEachNames.Contains(name);
-        }
-
-        return false;
-    }
 
     private static (string? FullyQualifiedName, string? AssemblyQualifiedName, bool IsRelationship, bool IsSingleton) ExtractComponentType(
         GeneratorSyntaxContext ctx, CancellationToken _)
@@ -154,44 +129,11 @@ public class ComponentDiscoveryGenerator : IIncrementalGenerator
         return (fqn, aqn, isRelationship, isSingleton);
     }
 
-    private static ImmutableArray<(string FullyQualifiedName, string AssemblyQualifiedName, bool IsRelationship)> ExtractForEachTypes(
-        GeneratorSyntaxContext ctx, CancellationToken _)
-    {
-        if (ctx.Node is not InvocationExpressionSyntax invocation)
-            return ImmutableArray<(string, string, bool)>.Empty;
 
-        if (invocation.Expression is not MemberAccessExpressionSyntax memberAccess)
-            return ImmutableArray<(string, string, bool)>.Empty;
-
-        if (memberAccess.Name is not GenericNameSyntax genericName)
-            return ImmutableArray<(string, string, bool)>.Empty;
-
-        var types = ImmutableArray.CreateBuilder<(string, string, bool)>();
-        foreach (var typeArg in genericName.TypeArgumentList.Arguments)
-        {
-            var symbolInfo = ctx.SemanticModel.GetSymbolInfo(typeArg);
-            if (symbolInfo.Symbol is INamedTypeSymbol typeSymbol &&
-                typeSymbol.IsValueType && !typeSymbol.IsAbstract &&
-                typeSymbol.DeclaredAccessibility == Accessibility.Public)
-            {
-                var fqn = typeSymbol.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat);
-                var aqn = typeSymbol.ContainingAssembly != null
-                    ? $"{typeSymbol.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat.WithGlobalNamespaceStyle(SymbolDisplayGlobalNamespaceStyle.Omitted))}, {typeSymbol.ContainingAssembly.Name}"
-                    : fqn;
-                bool isRelationship = typeSymbol.AllInterfaces.Any(i =>
-                    i.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat) == "global::OECS.IRelationship");
-                types.Add((fqn, aqn, isRelationship));
-            }
-        }
-
-        return types.ToImmutable();
-    }
 
     private static void GenerateRegistry(SourceProductionContext context,
-        (ImmutableArray<(string FullyQualifiedName, string AssemblyQualifiedName, bool IsRelationship, bool IsSingleton)> Left,
-         ImmutableArray<(string FullyQualifiedName, string AssemblyQualifiedName, bool IsRelationship)> Right) data)
+        ImmutableArray<(string FullyQualifiedName, string AssemblyQualifiedName, bool IsRelationship, bool IsSingleton)> invocations)
     {
-        var (invocations, forEachTypes) = data;
 
         // Collect unique types by fully-qualified name, deduplicating.
         var typeMap = new Dictionary<string, (string Fqn, string Aqn, bool IsRel, bool IsSingleton)>();
@@ -202,16 +144,6 @@ public class ComponentDiscoveryGenerator : IIncrementalGenerator
             else
                 typeMap[t.FullyQualifiedName] = (t.FullyQualifiedName, t.AssemblyQualifiedName, t.IsRelationship, t.IsSingleton);
         }
-        foreach (var t in forEachTypes)
-        {
-            if (!typeMap.ContainsKey(t.FullyQualifiedName))
-                typeMap[t.FullyQualifiedName] = (t.FullyQualifiedName, t.AssemblyQualifiedName, t.IsRelationship, false);
-            else if (t.IsRelationship)
-            {
-                var existing = typeMap[t.FullyQualifiedName];
-                typeMap[t.FullyQualifiedName] = (existing.Fqn, existing.Aqn, true, existing.IsSingleton);
-            }
-        }
 
         if (typeMap.Count == 0)
             return;
diff --git a/OECS/World.cs b/OECS/World.cs
index 8c0c7fd..403ef28 100644
--- a/OECS/World.cs
+++ b/OECS/World.cs
@@ -194,6 +194,11 @@ public class World : IDisposable
             nameof(AddComponentImpl),
             System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance)!;
 
+    private static readonly System.Reflection.MethodInfo s_removeComponentImpl =
+        typeof(World).GetMethod(
+            nameof(RemoveComponentImpl),
+            System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance)!;
+
     private void AddComponentImpl<T>(Entity entity, T component) where T : struct
     {
         ThrowIfNotAlive(entity);
@@ -589,20 +594,13 @@ public class World : IDisposable
             switch (m.Kind)
             {
                 case PendingMutationKind.AddComponent:
-                    // Use reflection to call AddComponentImpl<T>.
-                    var addMethod = typeof(World).GetMethod(
-                        nameof(AddComponentImpl),
-                        System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance)!;
-                    var genericAdd = addMethod.MakeGenericMethod(m.ComponentType);
-                    genericAdd.Invoke(this, [m.Entity, m.Component]);
+                    s_addComponentImpl.MakeGenericMethod(m.ComponentType)
+                        .Invoke(this, [m.Entity, m.Component]);
                     break;
 
                 case PendingMutationKind.RemoveComponent:
-                    var removeMethod = typeof(World).GetMethod(
-                        nameof(RemoveComponentImpl),
-                        System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance)!;
-                    var genericRemove = removeMethod.MakeGenericMethod(m.ComponentType);
-                    genericRemove.Invoke(this, [m.Entity]);
+                    s_removeComponentImpl.MakeGenericMethod(m.ComponentType)
+                        .Invoke(this, [m.Entity]);
                     break;
 
                 case PendingMutationKind.DestroyEntity:
diff --git a/docs/api-surface.md b/docs/api-surface.md
index 242598a..4b45551 100644
--- a/docs/api-surface.md
+++ b/docs/api-surface.md
@@ -379,7 +379,6 @@ namespace OECS;
 
 public interface IRelationship
 {
-    Entity Source { get; }
     Entity Target { get; }
 }
 ```
@@ -399,8 +398,7 @@ namespace OECS;
 public struct Relationship<TSelf, TTarget> : IRelationship
     where TSelf : struct where TTarget : struct
 {
-    [Key(0)] public Entity Source { get; set; }
-    [Key(1)] public Entity Target { get; set; }
+    [Key(0)] public Entity Target { get; set; }
 }
 ```
 
@@ -424,7 +422,8 @@ public enum ChangeKind
     EntityRemoved,
     ComponentAdded,
     ComponentRemoved,
-    ComponentModified
+    ComponentModified,
+    RelationshipReordered
 }
 ```