diff --git a/data/units/Merman.cfg b/data/units/Merman.cfg
index a1b85b58ab3..90b0ffc432d 100644
--- a/data/units/Merman.cfg
+++ b/data/units/Merman.cfg
@@ -1,5 +1,8 @@
+# XXX This unit is obsolete and should not be used anymore. It is here only for compatibility purposes and will be removed after few releases
+
 [unit]
 id=Merman
+obsolete=yes
 name= _ "Merman"
 race=merman
 image=merman.png
diff --git a/data/units/Merman_Hoplite.cfg b/data/units/Merman_Hoplite.cfg
index 7b7a91e13bb..1ae2546a6db 100644
--- a/data/units/Merman_Hoplite.cfg
+++ b/data/units/Merman_Hoplite.cfg
@@ -15,11 +15,11 @@ movement_type=swimmer
     [/defense]
 # The following resistance adjustments are to slightly downpower steadfast, yet keep the effect of it only activating during defense.  There is no adjustment for holy because attacking living units with holy should not be potent.
     [resistance]
-    blade=120
-    pierce=120
-    cold=60
-    fire=110
-    impact=110
+    blade=110
+    pierce=110
+    cold=70
+    fire=120
+    impact=100
     [/resistance]
 movement=5
 experience=500
@@ -35,7 +35,7 @@ get_hit_sound=mermen-hit.wav
 	name=trident
 	type=pierce
 	range=short
-	damage=9
+	damage=13
 	number=2
 		[frame]
 		begin=-100
diff --git a/data/units/Naga-Fighter.cfg b/data/units/Naga-Fighter.cfg
index 6542c3fc15c..5e9478caf95 100644
--- a/data/units/Naga-Fighter.cfg
+++ b/data/units/Naga-Fighter.cfg
@@ -5,7 +5,7 @@ race=naga
 gender=male,female
 image=naga-fighter.png
 image_defensive=naga-fighter-defend.png
-hitpoints=27
+hitpoints=30
 movement_type=naga
 movement=7
 experience=25
@@ -36,7 +36,7 @@ get_hit_sound=hiss.wav
         gender=female
         image=naga-fighter+female.png
         image_defensive=naga-fighter+female-defend.png
-        hitpoints=27
+        hitpoints=30
         movement_type=naga
         movement=7
         experience=25
diff --git a/data/units/Triton.cfg b/data/units/Triton.cfg
index 4ab36c9cbe7..5dee4765fbe 100644
--- a/data/units/Triton.cfg
+++ b/data/units/Triton.cfg
@@ -1,5 +1,8 @@
+# XXX This unit is obsolete and should not be used anymore. It is here only for compatibility purposes and will be removed after few releases
+
 [unit]
 id=Triton
+obsolete=yes
 name= _ "Triton"
 race=merman
 image=merman-king.png