Make HoOA confuse the hero, summon erinyes

A helmet psychically reaching inside your head and twiddling knobs in
your brain must be a confusing experience.  And the instant rejection of
your god (not to mention the vow that you made to find the amulet for
them), perhaps on the very cusp of their ascendance over the other gods,
is sort of the ultimate oathbreaking, so it interests the erinyes.

src/makemon.c

@@ -2452,4 +2452,15 @@ bagotricks(
     return moncount;
 }
 
+/* create some or all remaining erinyes around the player */
+void
+summon_furies(int limit) /* number to create, or 0 to create until extinct */
+{
+    int i = 0;
+    while (mk_gen_ok(PM_ERINYS, G_GONE, 0U) && (i < limit || !limit)) {
+        makemon(&mons[PM_ERINYS], u.ux, u.uy, MM_ADJACENTOK | MM_NOWAIT);
+        i++;
+    }
+}
+
 /*makemon.c*/