diff --git a/DATabase/DATabase.cs b/DATabase/DATabase.cs
index 48f7b253..b2099605 100644
--- a/DATabase/DATabase.cs
+++ b/DATabase/DATabase.cs
@@ -874,7 +874,7 @@ Make a selection:
     4) Category" + (cat != "" ? ":\t" + cat : "") + @"
     5) Version" + (version != "" ? ":\t" + version : "") + @"
     6) Author" + (author != "" ? ":\t" + author : "") + @"
-    7) " + (ad ? "Only output normal diff" : "Output all diff variants") + @"
+    7) " + (ad ? "Only output normal diff" : "Output all diff variants (2 files only)") + @"
     8) " + (dedup ? "Don't dedup files in output" : "Dedup files in output") + @"
     9) " + (diff ? "Only merge the input files" : "Diff the input files") + @"
     10) " + (bare ? "Don't append the date to the name" : "Append the date to the name") + @"
diff --git a/DATabase/MergeDiff.cs b/DATabase/MergeDiff.cs
index b0514932..cbc071ec 100644
--- a/DATabase/MergeDiff.cs
+++ b/DATabase/MergeDiff.cs
@@ -81,29 +81,7 @@ namespace SabreTools
 				return false;
 			}
 
-			List<RomData> A = new List<RomData>();
-
-			foreach (string input in _inputs)
-			{
-				_logger.Log("Adding DAT: " + input);
-				List<RomData> B = RomManipulation.Parse(input, 0, 0, _logger);
-				if (_diff)
-				{
-					A = RomManipulation.Diff(A, B);
-				}
-				else
-				{
-					A.AddRange(B);
-				}
-			}
-
-			// If we want a merged list, send it for merging before outputting
-			if (_dedup)
-			{
-				A = RomManipulation.Merge(A);
-			}
-
-			// Get the names that will be used
+			// Get the values that will be used
 			if (_name == "")
 			{
 				_name = (_diff ? "diffdat" : "mergedat") + (_dedup ? "-merged" : "");
@@ -125,6 +103,46 @@ namespace SabreTools
 				_author = "SabreTools";
 			}
 
+			List<RomData> A = new List<RomData>();
+
+			foreach (string input in _inputs)
+			{
+				_logger.Log("Adding DAT: " + input);
+				List<RomData> B = RomManipulation.Parse(input, 0, 0, _logger);
+				if (_diff)
+				{
+					A = RomManipulation.Diff(A, B);
+				}
+				else
+				{
+					A.AddRange(B);
+				}
+			}
+
+			// If we're in Alldiff mode, we can only use the first 2 inputs
+			if (_ad)
+			{
+				List<RomData> AB1 = RomManipulation.Parse(_inputs[0], 0, 0, _logger);
+				List<RomData> AB2 = RomManipulation.Parse(_inputs[1], 0, 0, _logger);
+
+				List<RomData> OnlyA = RomManipulation.DiffOnlyInA(AB1, AB2);
+				List<RomData> OnlyB = RomManipulation.DiffOnlyInA(AB2, AB1);
+				List<RomData> BothAB = RomManipulation.DiffInAB(AB1, AB2);
+
+				string input0 = Path.GetFileNameWithoutExtension(_inputs[0]);
+				string input1 = Path.GetFileNameWithoutExtension(_inputs[1]);
+
+				Output.WriteToDat(_name + "-" + input0 + "-only", _desc + "-" + input0 + "-only", _version, _date, _cat, _author, _forceunpack, _old, "", OnlyA, _logger);
+				Output.WriteToDat(_name + "-" + input1 + "-only", _desc + "-" + input1 + "-only", _version, _date, _cat, _author, _forceunpack, _old, "", OnlyB, _logger);
+				Output.WriteToDat(_name + "-inboth", _desc + "-inboth", _version, _date, _cat, _author, _forceunpack, _old, "", BothAB, _logger);
+			}
+
+			// If we want a merged list, send it for merging before outputting
+			if (_dedup)
+			{
+				A = RomManipulation.Merge(A);
+			}
+
 			// Now write the file out
 			Output.WriteToDat(_name, _desc, _version, _date, _cat, _author, _forceunpack, _old, "", A, _logger);
 
diff --git a/SabreHelper/Build.cs b/SabreHelper/Build.cs
index 8378cfdd..5d0ec908 100644
--- a/SabreHelper/Build.cs
+++ b/SabreHelper/Build.cs
@@ -118,7 +118,7 @@ Options:
   -lso, --list-sources	List all sources (id <= name)
   -lsy, --list-systems	List all systems (id <= name)
   -m, --merge		Merge two or more DATs
-	-ad, --all-diff	Enable output of all diff variants
+	-ad, --all-diff	Enable output of all diff variants (2 DATs only)
 	-di, --diff		Switch to diffdat mode
 	-dd, --dedup		Enable deduping in the created DAT
 	-b, --bare		Don't include date in file name