Use {IS_HERO}

data/campaigns/The_South_Guard/scenarios/1.Born_To_The_Banner.cfg

@@ -39,7 +39,7 @@
 	{QUANTITY type (Horseman Commander) (Junior Commander) (Junior Commander)}
 	description=Deoran
 	user_description= _ "Deoran"
-	overlays="misc/hero-icon.png"
+	{IS_HERO}
 	unrenamable=yes
 
 	team_name=South_Guard
@@ -235,7 +235,7 @@
 		type=South Guard Captain
 		description=Sir Gerrick
 		user_description= _ "Sir Gerrick"
-		overlays="misc/hero-icon.png"
+		{IS_HERO}
 		x,y=14,9
 		traits_description=_"valiant," + _"resilient" 
 		[modifications]

data/campaigns/The_South_Guard/scenarios/2.Proven_By_The_Sword.cfg

@@ -230,7 +230,7 @@
 		type=White Mage
 		description=Minister Hylas
 		user_description= _ "Minister Hylas"
-		overlays="misc/hero-icon.png"
+		{IS_HERO}
 		side=1
 		x,y=21,16
 		traits_description=_"loyal," + _"intellegent" 

data/campaigns/The_South_Guard/scenarios/3.A_Desparate_Errand.cfg

@@ -262,7 +262,7 @@
 			#endif
 			description=Ethiliel
 			user_description= _ "Ethiliel"
-			overlays="misc/hero-icon.png"
+			{IS_HERO}
 			side=1
 			x,y=18,6
 			[modifications]