diff --git a/doc/fixes37.0 b/doc/fixes37.0
index 907fcbd04..d1d2cf104 100644
--- a/doc/fixes37.0
+++ b/doc/fixes37.0
@@ -491,6 +491,8 @@ some rolling boulder trap feedback was inconsistent
 change "killed by <a foo>, while {paralyzed|frozen} by <a foo>" into
 	"killed by <a foo>, while {paralyzed|frozen}" if the killer caused
 	hero's helplessness
+"It looks very angry" would be given if a hero wielding Excalibur or Demonbane
+	offended an unseen demon lord
 
 
 Fixes to 3.7.0-x Problems that Were Exposed Via git Repository
diff --git a/src/minion.c b/src/minion.c
index 54869a8bd..faf30590c 100644
--- a/src/minion.c
+++ b/src/minion.c
@@ -225,7 +225,10 @@ demon_talk(register struct monst *mtmp)
 
     if (uwep && (uwep->oartifact == ART_EXCALIBUR
                  || uwep->oartifact == ART_DEMONBANE)) {
-        pline("%s looks very angry.", Amonnam(mtmp));
+        if (canspotmon(mtmp))
+            pline("%s looks very angry.", Amonnam(mtmp));
+        else
+            You_feel("tension building.");
         mtmp->mpeaceful = mtmp->mtame = 0;
         set_malign(mtmp);
         newsym(mtmp->mx, mtmp->my);