diff --git a/th04/main/midboss/midboss.hpp b/th04/main/midboss/midboss.hpp
new file mode 100644
index 00000000..89618c19
--- /dev/null
+++ b/th04/main/midboss/midboss.hpp
@@ -0,0 +1,31 @@
+typedef struct {
+	motion_t pos;
+	unsigned int frames_until;
+	int hp;
+	unsigned char sprite;
+	unsigned char phase;
+	int phase_frame;
+	// Treated as a bool in TH04
+	unsigned char damage_this_frame;
+	unsigned char angle;
+} midboss_stuff_t;
+
+extern midboss_stuff_t midboss;
+
+// Callbacks
+extern  farfunc_t_near midboss_update_func;
+extern nearfunc_t_near midboss_render_func;
+
+#define MIDBOSS_DEC(stage) \
+	void pascal  far midboss##stage##_update(void); \
+	void pascal near midboss##stage##_render(void);
+
+// "midbosses" unfortunately has 9 characters and therefore won't work as a
+// 8.3 filename. However, since these have no names anyway, we can just
+// declare all of them here.
+MIDBOSS_DEC(1);
+MIDBOSS_DEC(2);
+MIDBOSS_DEC(3);
+MIDBOSS_DEC(4);
+MIDBOSS_DEC(5);
+MIDBOSS_DEC(x);
diff --git a/th04/shared.hpp b/th04/shared.hpp
index 6f0cd350..17603ae7 100644
--- a/th04/shared.hpp
+++ b/th04/shared.hpp
@@ -32,31 +32,6 @@ extern nearfunc_t_near stage_invalidate;
 extern nearfunc_t_near stage_render;
 /// ------
 
-/// Midbosses
-/// ---------
-typedef struct {
-	motion_t pos;
-	unsigned int frames_until;
-	int hp;
-	unsigned char sprite;
-	unsigned char phase;
-	int phase_frame;
-	// Treated as a bool in TH04
-	unsigned char damage_this_frame;
-	unsigned char angle;
-} midboss_stuff_t;
-
-extern midboss_stuff_t midboss;
-
-// Callbacks
-extern  farfunc_t_near midboss_update_func;
-extern nearfunc_t_near midboss_render_func;
-
-#define MIDBOSS_DEC(stage) \
-	void pascal  far midboss##stage##_update(void); \
-	void pascal near midboss##stage##_render(void);
-/// ---------
-
 /// Score
 /// -----
 extern unsigned long score_delta;
diff --git a/th05/main/stage/setup.cpp b/th05/main/stage/setup.cpp
index 23aabd49..1dfeaead 100644
--- a/th05/main/stage/setup.cpp
+++ b/th05/main/stage/setup.cpp
@@ -3,6 +3,8 @@
  * TH05 stage initialization
  */
 
+#include "th04/main/midboss/midboss.hpp"
+
 void pascal near stage1_setup(void)
 {
 	midboss_update_func = midboss1_update;
diff --git a/th05/th05.hpp b/th05/th05.hpp
index 2979c5e2..8ff9f671 100644
--- a/th05/th05.hpp
+++ b/th05/th05.hpp
@@ -19,16 +19,6 @@ void pascal near stage2_update(void);
 void pascal near stage2_invalidate(void);
 /// ------
 
-/// Midbosses
-/// ---------
-MIDBOSS_DEC(1);
-MIDBOSS_DEC(2);
-MIDBOSS_DEC(3);
-MIDBOSS_DEC(4);
-MIDBOSS_DEC(5);
-MIDBOSS_DEC(x);
-/// ---------
-
 /// Bosses
 /// ------
 #include "th05/main/boss/boss.hpp"